Fix 1130 and 1102

[kapedalex]

Description

Moved wandb import and initialization inside the train function to make it an optional dependency. Added is_library_available check to prevent crashes if wandb is not installed and for future reference.

Fixes #1130 and #1102

Type of change

• Bug fix

Checklist:

• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• I have not rewritten tests relating to key interfaces which would affect backward compatibility

[kapedalex]

As I can see there are only 'No space left on device' errors, so tests passed.
To fix them we could use this: https://github.com/jlumbroso/free-disk-space, but I worry it might break home runner. I will leave link here as potential solution for later.