[26.0] Fixes navigation back to added URLs in upload panel

[davelopez]

xref

Fixes:

So, here, if you add a URL, but then you click Add More URLs, then... how do you go back to that list of currently added (but not uploaded yet) URLs?

Adds UI controls to switch between URL input and the list of added URLs, making it possible to review and manage previously added links.

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:
  • Add some links
  • Click "Add More URLs"
  • Now you have a way to go back to the added URLs view

License

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

[davelopez]

Selenium test failure TestSavedHistories::test_rename_history unrelated.