Job resource parameters selector broken on usegalaxu.eu (unknown causes)

[kysrpex]

Describe the bug
The job resource parameters selector broke on usegalaxy.eu. For the tool keras_train_and_eval, the option "Use GPU resources" shows up, but no drop-down menu is available and no items can be selected.

Galaxy Version and/or server at which you observed the bug
Galaxy Version: 23.1rc1
Commit: 248078bacc45776a7cca26183b663208a7eadb82 (from the usegalaxy-eu/galaxy fork)

To Reproduce
Steps to reproduce the behavior:

1. Visit the keras_train_and_eval tool page.
2. Select "Specify job resource parameters" under "Job Resource Parameters".
3. The parameter "Use GPU resources" shows up.
4. The message "No options available." is shown under the parameter's label.

Expected behavior
Two options ("No (default)", "Yes") should be available in the drop-down menu. In fact, this was working a few days/weeks ago.

Screenshots

Additional context
After debugging this issue, the options are available in the XML nodes tagged with "param" here. They are then returned and later retrieved, but by then, the children of the XML node (the options) are gone.

I do not think this is a Galaxy bug but rather something related either to lxml or whatever is doing the garbage collection. On a local Galaxy instance I have in a VM this is not happening.

I have proposed a workaround in #16728.

[kysrpex]

@anuprulez This is the problem you mentioned yesterday, and as you can see I have also proposed a solution. I think it makes sense to mention you here so that you get notified when the issue gets closed.