Describe the bug
The attached FITS image is from Herschel space telescope. The image can be loaded successfully in v3-stable but not in v4-beta nor dev.

2023-05-16 03:20:11 INFO FITSCoordinateUtil::fromFITSHeader passing empty or nonexistant spectral Coordinate axis
[2023-05-16 03:20:11.140] [CARTA] [debug] Extended file info exception: Unit::check Illegal unit string 'degrees'
2023-05-16 03:20:11 INFO FITSCoordinateUtil::fromFITSHeader passing empty or nonexistant spectral Coordinate axis
[2023-05-16 03:20:11.144] [CARTA] [debug] Extended file info exception: Unit::check Illegal unit string 'degrees'
[2023-05-16 03:20:11.144] [CARTA] [error] Header error or no image HDUs found.

https://drive.google.com/file/d/1mxo4YO6H7zLq9T1eZnHBnGpfe1ITKoEl/view?usp=sharing

To Reproduce
Steps to reproduce the behavior:

1. download the test image and try to load it in carta
2. when we click on the image file in the file browser, we will see error in the file info pane.

Expected behavior
The image can be loaded successfully

Platform info (please complete the following information):

• OS [e.g. macOS Monterey]: macOS Ventura
• Browser [e.g. chrome, safari, electron app]: chrome (dev) electron app (v4-beta)
• Browser version [e.g. 22]: chrome-113
• Backend branch [e.g. dev, v3b2 release]: v4-beta, dev
• Frontend branch [e.g. dev, v3b2 release]: v4-beta, dev