Sync provider settings with settings.yml in config UI (#5270)

# Description of Changes

This pull request improves the handling of provider settings in the
`ProviderCard` component to ensure settings are always in sync with the
latest values from `settings.yml`, and enhances how default values are
initialized for provider fields. It also updates the usage of
`ProviderCard` in the admin connections section to explicitly pass
provider settings.

**Provider settings synchronization and initialization:**

* Added a `useEffect` in `ProviderCard` to keep `localSettings` in sync
with incoming `settings` prop, ensuring that changes from `settings.yml`
are reflected in the UI.
* Improved default value initialization in `ProviderCard`: when opening
an unconfigured provider, it now merges defaults with any existing
values from `settings.yml`, rather than overwriting them.

**Integration with AdminConnectionsSection:**

* Updated `AdminConnectionsSection` to explicitly pass provider settings
to `ProviderCard` via the `settings` prop, ensuring the component always
receives the correct configuration.

---

## Checklist

### General

- [ ] I have read the [Contribution
Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md)
- [ ] I have read the [Stirling-PDF Developer
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md)
(if applicable)
- [ ] I have read the [How to add new languages to
Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md)
(if applicable)
- [ ] I have performed a self-review of my own code
- [ ] My changes generate no new warnings

### Documentation

- [ ] I have updated relevant docs on [Stirling-PDF's doc
repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/)
(if functionality has heavily changed)
- [ ] I have read the section [Add New Translation
Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/HowToAddNewLanguage.md#add-new-translation-tags)
(for new translation tags only)

### UI Changes (if applicable)

- [ ] Screenshots or videos demonstrating the UI changes are attached
(e.g., as comments or direct attachments in the PR)

### Testing (if applicable)

- [ ] I have tested my changes locally. Refer to the [Testing
Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/devGuide/DeveloperGuide.md#6-testing)
for more details.

frontend/src/proprietary/components/shared/config/configSections/AdminConnectionsSection.tsx

@@ -422,6 +422,7 @@ export default function AdminConnectionsSection() {
                 key={provider.id}
                 provider={provider}
                 isConfigured={false}
+                settings={getProviderSettings(provider)}
                 onSave={(providerSettings) => handleProviderSave(provider, providerSettings)}
                 disabled={!loginEnabled}
               />