[26.0] Fixes some more optional fields in templates

[davelopez]

Follow up to #21704

These repositories allow access to the contents that are public without having to specify a token or set a publication name if we are going to use them just for read-only purposes.

How to test the changes?

• I've included appropriate automated tests.
• This is a refactoring of components with existing test coverage.
• Instructions for manual testing are as follows:
  • Include any of these templates in your config/file_source_templates.yml
  • Try to create a connection and see that the API token and publication name are now optional.

License

• I agree to license these and all my past contributions to the core galaxy codebase under the MIT license.