Submit data entry from frontend to backend API

[lkleuver]

No description provided.

[praseodym]

Could you rebase this branch to get rid of the commits that were already merged to the main branch in older PRs?

[jschuurk-kr]

@lkleuver I'm trying to build a test similar to the example in the React Testing Library docs and am running into two issues.

1. There's no easy way to add a handler to the mock that overrides the default ones for a specific test.

2. I extended VotersAndVotesForm.test.tsx to click the button and check for the success and/or error element in the page. Even after I make sure startMockAPI() is not called in app/main.tsx, when I run the test, the DOM still contains <p>id="success">Success</p>. So it seems the mock returns a response, even though it's not running?

The only way so far I've found to get the error <p>-element in the DOM is by changing the pollingStationDataEntryHandler to return a 422 if "voters_counts" in json.data.

[praseodym]

I think I fixed the current CI error in 7f8658a but that commit got replaced by an older one by accident. Could you rebase and pick 7f8658a instead of cc49795?

[praseodym]

Looks good, just two minor comments.

[praseodym]

The failing Vercel check can be ignored, this is a remnant of me testing Vercel for PR deploys. I'm testing this in a test repository instead :)