Resolve "After applying new file template commit change button doesn't enable"

What does this MR do?

Enables the Commit Changes button on the New File page when a file template is applied

Are there points in the code the reviewer needs to double check?

None. This change seems minor enough to not warrant a system test, but let me know if one is needed

Why was this MR needed?

As mentioned in #42689 (closed), when a template is applied to a new file the Commit Changes button remains disabled

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• [-] Documentation created/updated
• [-] API support added
• [-] Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • [-] Has been reviewed by Backend
  • [-] Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• [-] Internationalization required/considered
• [-] End-to-end tests pass (package-qa manual pipeline job)

What are the relevant issue numbers?

#42689 (closed)