Handle TypeError in Live Viewer due to slow FITS files

[MikeSullivan7]

Issue Closes #2469

Description

When loading an image inside display_image, we now include TypeError to catch the instance when the Live Viewer attempts to read a FITS file that has not completed moving to the LV path, leading to a TypeError raise from astropy.

Developer Testing

tests pass with make check and make test-system

Acceptance Criteria and Reviewer Testing

• Unit tests pass locally: make check and make test-system
• Open the LV and transfer FITS files to the path via python simulate_live_data.py using --mode slow
• Check that no error dialogs appear, even if errors and warnings appear in the terminal

Documentation and Additional Notes

• Release Notes have been updated

[coveralls]

coverage: 73.116% (+0.002%) from 73.114%
when pulling dbf119b on 2469_LV_slow_fits
into 1166cb4 on main.