Set busy cursor while loading environment

[michaellans]

Introduces a new gui util for setting the cursor to provide visual feedback during slow GUI operations.

• Added with_busy_cursor decorator to gui/utils.py, which wraps the decorated function with set_busy_cursor and unset_busy_cursor. The cursor indicates a busy state while a decorated function runs, and resets afterward.

• Applied @with_busy_cursor to select_env in routine_page.py

• Added unset_busy_cursor in expandable_message_box.py so that if an error message is shown, the cursor will revert to normal.

[michaellans]

This seems to work well, I updated the status message at the end to be a bit more descriptive.

[roussel-ryan]

@michaellans I may have messed up merging in from main, can you fix the linting issues and test issues and then I can approve

[michaellans]

I think it was just from reorganizing the imports, should be fixed.