MPDX-9241 Replace cancel with discard button

[kegrimes]

Description

Based on new figma designs, we must replace "Cancel" with "Discard" button and update the submit modal text.

Testing

Testing Edit page discard button (In Progress status):

• Go to /reports/housingAllowance
• Click "Edit Request" and click "Discard Changes"
• Check that submit modal has correct text
• Click "Yes, Discard Changes"
• Check that the request was deleted and it redirected user to dashboard page

Testing New page discard button (In Progress status):

• Click "Request New MHA" and click "Discard"
• Check that submit modal has correct text
• Click "Yes, Discard"
• Check that the request was deleted and it redirected user to dashboard page

Testing cancel button (In Progress status):

• Click "Request New MHA" and click back arrow icon to go back to dashboard
• Click "Cancel Request"
• Check that submit modal has correct text
• Click "Yes, Cancel"
• Check that the request was deleted

Testing cancel button (Pending status)

• Click "Request New MHA"
• Input all valid data and submit request form
• Go back to dashboard page
• Click "Cancel Request" and click "Yes, Cancel"
• Check that the request was deleted
• Check database records and ensure status is cancelled

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]

Preview branch generated at https://mpdx-9241-add-discard-button.d3dytjb8adxkk5.amplifyapp.com

[github-actions]

Bundle sizes [mpdx-react]

Compared against 26b469f

No significant changes found

[kegrimes]

@dr-bizz Since a user is not allowed to edit when a request is pending, should we remove the edit link option on the Receipt page? When a user submits their request, the status will become pending, so they shouldn't have an option to edit. Currently, if a user clicks that link, it will take them to "Edit Access Denied" page.

[dr-bizz]

Approving this, but found some small things