chore(1-3679): use numeric input mode for numbers. (#9875)

Adds inputmode='decimal' to input fields with number input. As discussed
on the [GOV.UK
blog](https://technology.blog.gov.uk/2020/02/24/why-the-gov-uk-design-system-team-changed-the-input-type-for-numbers/),
this finds a balance between giving numeric input options to mobile
devices and improving validation / user experience.

They mention this bit in their [design system
guideline](https://design-system.service.gov.uk/components/text-input/#numbers)

> Do not use `<input type="number">` unless your user research shows
that there’s a need for it. With `<input type="number">` there’s a risk
of users accidentally incrementing a number when they’re trying to do
something else - for example, scroll up or down the page. And if the
user tries to enter something that’s not a number, there’s no explicit
feedback about what they’re doing wrong.

I've purposefully not included the `pattern="[0-9]*"` attribute here,
because the browser error messages conflict with our own and have
several drawbacks in terms of accessibility according to Adrian
Roselli's ["Avoid default field
validation"](https://adrianroselli.com/2019/02/avoid-default-field-validation.html).

Instead, the validation here will be part of the validation handling
later.

Also, I've opted for using `decimal` instead of `numeric`, because we
allow you to store decimal values and that inputmode also adds the
decimal separator to the keyboard. As always, however, there's
complications: several languages (including Norwegian) use a comma as a
decimal separator instead of a period, so the keyboard will likely
contain numbers and a comma instead of a period. This is a problem
because JS doesn't recognize "45,6" as a valid number. I've added a
follow-up task to look into this. I thought at first it would just be
expanding the validation, but because it's stored as a string on the
back end and the SDKs presumably parse it, we can't just suddenly allow
commas as decimal separators.

frontend/src/component/feature/FeatureStrategy/FeatureStrategyConstraints/AddSingleValueWidget.tsx

@@ -17,15 +17,16 @@ const StyledChip = styled(ValueChip, {
     },
 }));
 
-interface AddValuesProps {
+type Props = {
     onAddValue: (newValue: string) => void;
     removeValue: () => void;
     currentValue?: string;
     helpText?: string;
-}
+    inputType: 'text' | 'number';
+};
 
-export const AddSingleValueWidget = forwardRef<HTMLDivElement, AddValuesProps>(
-    ({ currentValue, onAddValue, removeValue, helpText }, ref) => {
+export const AddSingleValueWidget = forwardRef<HTMLDivElement, Props>(
+    ({ currentValue, onAddValue, removeValue, helpText, inputType }, ref) => {
         const [open, setOpen] = useState(false);
         const positioningRef = useRef<HTMLDivElement>(null);
         useImperativeHandle(
@@ -55,6 +56,9 @@ export const AddSingleValueWidget = forwardRef<HTMLDivElement, AddValuesProps>(
                     onDelete={currentValue ? removeValue : undefined}
                 />
                 <AddValuesPopover
+                    inputProps={{
+                        inputMode: inputType === 'number' ? 'decimal' : 'text',
+                    }}
                     initialValue={currentValue}
                     onAdd={handleAdd}
                     helpText={helpText}

frontend/src/component/feature/FeatureStrategy/FeatureStrategyConstraints/AddValuesPopover.tsx

@@ -1,4 +1,10 @@
-import { Button, Popover, styled, TextField } from '@mui/material';
+import {
+    Button,
+    type InputBaseComponentProps,
+    Popover,
+    styled,
+    TextField,
+} from '@mui/material';
 import { ScreenReaderOnly } from 'component/common/ScreenReaderOnly/ScreenReaderOnly';
 import { type FC, useId, useRef, useState } from 'react';
 
@@ -34,6 +40,7 @@ type AddValuesProps = {
     anchorEl: HTMLElement | null;
     onClose: () => void;
     helpText?: string;
+    inputProps?: InputBaseComponentProps;
 };
 
 const HelpText = styled('p')(({ theme }) => ({
@@ -52,6 +59,7 @@ export const AddValuesPopover: FC<AddValuesProps> = ({
     open,
     onClose,
     helpText,
+    inputProps,
 }) => {
     const [inputValue, setInputValue] = useState(initialValue || '');
     const [error, setError] = useState('');
@@ -119,6 +127,9 @@ export const AddValuesPopover: FC<AddValuesProps> = ({
                         error={!!error}
                         helperText={error}
                         aria-describedby={helpTextId}
+                        inputProps={{
+                            ...inputProps,
+                        }}
                     />
                     <AddButton
                         variant='text'

frontend/src/component/feature/FeatureStrategy/FeatureStrategyConstraints/EditableConstraint.tsx

@@ -303,6 +303,9 @@ export const EditableConstraint: FC<Props> = ({
                                 ? 'Add a single number'
                                 : 'A semver value should be of the format X.Y.Z'
                         }
+                        inputType={
+                            inputType.type === 'number' ? 'number' : 'text'
+                        }
                     />
                 );
             case 'multiple values':