[24.0] Fix Invenio credentials handling

[davelopez]

This fixes a regression introduced in #17997 where the user is forced to introduce credentials for Invenio/Zenodo even when just browsing public records.

The credentials are now required only for write operations.

Before	After

How to test the changes?

(Select all options that apply)

• [ ] I've included appropriate automated tests.
• [ ] This is a refactoring of components with existing test coverage.
• [x] Instructions for manual testing are as follows:
  • Without setting up your token in the preferences or as an anonymous user
  • Go to Upload -> Choose remote files -> select an Invenio based file source
  • You should be able to see the records instead of the error message

License

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