[25.1] Enable drag-and-drop of collection elements in IGV

[guerler]

Partially resolves #21057. See: galaxyproject/galaxy-visualizations#124

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.

[mvdbeek]

Thank you @guerler!