[23.2] Fix categories in ToolShed repo create API

[nsoranzo]

Fix #17215 .

Also:

• Add API test for creation of TS repo with multiple categories.

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.

[nsoranzo]

The "Test Galaxy packages" failure on Python 3.11:

/tmp/gxpkgtestenvBeDHo8/lib/python3.11/site-packages/trio/_core/_asyncgens.py:147: error: INTERNAL ERROR -- Please try using mypy master on GitHub:
https://mypy.readthedocs.io/en/stable/common_issues.html#using-a-development-mypy-build
If this issue continues with mypy master, please report a bug at https://github.com/python/mypy/issues
version: 1.4.1
/tmp/gxpkgtestenvBeDHo8/lib/python3.11/site-packages/trio/_core/_asyncgens.py:147: : note: please use --show-traceback to print a traceback when reporting a bug
make: *** [Makefile:96: mypy] Error 2

is unrelated. I've reproduced it locally and it goes away with mypy 1.7.1 (but not sure which version after 1.4.1 fixed it), but we cannot use a more recent mypy version because 1.4.1 is the last one supporting Python 3.7.

[jmchilton]

Awesome fix - thank you so much!