Replaces loading_button with gl-button

What does this MR do?

Replaces loading_button with gl-button that now has the loading prop

To test, you must have error tracking enabled.

1. Go to Operations -> Error Tracking
2. Click on any error, the buttons should be there

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines

This is one of a loooong series of MRs that will replace the loading button: #207412 (closed)