Catch cases where the segment doesn't exist and populate that error
message with more info: it now says that a segment
with <id> doesn't exist instead of just 'No row'.
Assume `undefined` instead of `null` for project in terms of interfacing
with segments: If the `project` field is not present, that means that it
is not set, which means we're dealing with a "global" segment. If we
want to unset `project` and make a segment global, we simply don't send
the `project` property on our PUT method.
~~Should we handle this on the store layer instead~~? 🤔
Fixing this on the store layer. Effectively, frontend is able to send
`project: null` and even if that gets magically converted to `""` it's
OK since we're covering that use case on the store layer. Backend
response will be `project: null` as well, so it should be consistent.
* First version ready
* Final
* Refactor
* Update pat store
* Website revert
* Website revert
* Update
* Revert website
* Revert docs to main
* Revert docs to main
* Fix eslint
* Test
* Fix table name
