Add Playwright tests for policy creation form views

[emmaaroche]

Objective

Add Playwright UI tests for new policy creation form views.

Details

Epic #378 will add form views to policies that currently only have YAML editors. We will need tests for new form functionality, validation, form/YAML toggle once they have been implemented.

Checklist

• OIDCPolicy form tests
• TokenRateLimitPolicy form tests
• PlanPolicy form tests
• RateLimitPolicy form tests
• AuthPolicy form tests