session resume failed if there is an LEL image

[kswang1029]

Describe the bug
If we have an image loaded via LEL (eg "dice_one.fits"+"dice_four.fits"), the session cannot be resumed and hangs forever.

To Reproduce
Steps to reproduce the behavior:

1. load an image via LEL
2. kill the backend
3. restart the backend
4. click the resume button and we will see errors

Expected behavior
A session should still be resumed if there was an LEL image. Since the LEL image is formed from in-disk images, we should still see the LEL image in a resumed session (unlike in-memory images such as generated moments/PV we don't resume such).

Platform info (please complete the following information):

• OS [e.g. macOS Monterey]: macOS Monterey
• Browser [e.g. chrome, safari, electron app]: chrome
• Browser version [e.g. 22]: 108
• Backend branch [e.g. dev, v3b2 release]: dev
• Frontend branch [e.g. dev, v3b2 release]: dev

[kswang1029]

done by #1264 CARTAvis/carta-protobuf#84 CARTAvis/carta-frontend#2159