refactor: 💡 remove dynamic component helper from form/authenticate

[hashicc]

Description

This pr continues the migration away from the dynamic {{component}} helper. More information in #2880. This pull request focuses on migrating the authenticate form component.

tickets: Jira ticket

How to Test

• Tests should pass
• Navigate to admin or desktop login screens, the form for each auth method should load correctly

Checklist

• I have added before and after screenshots for UI changes
• I have added JSON response output for API changes
• I have added steps to reproduce and test for bug fixes in the description
• I have commented on my code, particularly in hard-to-understand areas
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• I have added a11y-tests label to run a11y audit tests if needed

PCI review checklist

• I have documented a clear reason for, and description of, the change I am making.
• If applicable, I've documented a plan to revert these changes if they require more than reverting the pull request.
• If applicable, I've documented the impact of any changes to security controls.
  Examples of changes to security controls include using new access control methods, adding or removing logging pipelines, etc.

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Project	Deployment	Preview	Comments	Updated (UTC)
boundary-ui	Ready	Preview	Comment	Oct 6, 2025 3:13pm
boundary-ui-desktop	Ready	Preview	Comment	Oct 6, 2025 3:13pm