MPDX-9336, MPDX-9333, MPDX-9332 - ASR/MHA loading states upon creation, hide Current MHA Request if request DNE

[zweatshirt]

Description

• MPDX-9332 and MPDX-9333 are essentially duplicate issues
  • If a request didn't exist, currentRequest was being set as an empty object (empty objects are truthy). I replaced this with undefined.
• MPDX-9336 includes the desire for a loading state while waiting for the create mutation to resolve

Testing

• Go to /housingAllowance for MHA
• Determine that cancelling and having no existing requests correctly does not render CurrentRequest
• Check that the loading state during creation correctly aligns with the expectations of MPDX-9336
• Go to /additionalSalaryRequest and check that the loading state during creation correctly aligns with expectations of MPDX-9336

MPDX-9332
MPDX-9333
MPDX-9336

Checklist:

• I have given my PR a title with the format "MPDX-(JIRA#) (summary sentence max 80 chars)"
• I have applied the appropriate labels (Add the label "Preview" to automatically create a preview environment)
• I have run the Claude Code /pr-review command locally and fixed any relevant suggestions
• I have requested a review from another person on the project
• I have tested my changes in preview or in staging
• I have cleaned up my commit history

[github-actions]

Bundle sizes [mpdx-react]

Compared against f82890e

No significant changes found

[github-actions]

Preview branch generated at https://MPDX-9336.d3dytjb8adxkk5.amplifyapp.com

[zweatshirt]

@wjames111 I realize the useState in MHA is a little awkward. It was the only way I could figure out how to stop the page from flashing during the create mutation. If you happen to have any ideas for that, let me know! Thanks Will