Fix the bioblend test failures

[arash77]

This PR fixes Bioblend test failures by refactoring the library_content API logic. It now checks for files before assigning them to tool_params for uploading.

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.
• Instructions for manual testing are as follows:
  1. [add testing steps and prerequisites here if you didn't write automated tests covering all your changes]

License

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

[davelopez]

Thank you @arash77!