WCS corruption after opening image with bad header

[tvwenger]

Describe the bug
When opening an image with a bad header (in my case, the cube had "CTYPE1" = "RA-TAN" instead of "RA---TAN" and "CTYPE2" = "DEC-TAN" instead of "DEC--TAN"), CARTA complains about the WCS and fails to properly label the coordinates of the data. That's fine, as it's a problem with the data header.

The problem, however, is that any subsequent images (with good headers) opened in that same CARTA session also fail to properly load the WCS. That is, if I close the original (bad) image and open a different image (with a correct header), no proper coordinates are displayed for the image.

To Reproduce
Steps to reproduce the behavior:

1. Open this FITS cube with a good header in CARTA. Everything is fine.
2. Close that image, then open this FITS cube with a bad header. The CARTA log complains about the WCS, and CARTA fails to generate a coordinate system.
3. Close that image, and open the original good header image again. There are no errors in the CARTA log, and yet CARTA fails to generate a coordinate system.

Expected behavior
Whether or not a bad header was loaded should not impact CARTA's ability to load subsequent image coordinates within the same session.

Platform info (please complete the following information):

• OS [e.g. macOS Monterey]: Ubuntu/WSL
• Browser [e.g. chrome, safari, electron app]: Firefox
• Browser version [e.g. 22]: 127.0.2
• Backend branch [e.g. dev, v3b2 release]: 4.1.0
• Frontend branch [e.g. dev, v3b2 release]: 4.1.0

Additional context
Here's the CARTA log when opening the "bad header" image:

[2024-06-28 16:14:13.239Z] [CARTA] [info] Session 2312038391 [172.28.128.1] Connected. Num sessions: 1
[2024-06-28 16:14:27.120Z] [CARTA] [info] Could not find BEAMS table.
[2024-06-28 16:14:27.132Z] [CARTA] [warning] [casacore] Zero or no rest frequency provided for velocity axis.
[2024-06-28 16:14:27.135Z] [CARTA] [warning] [casacore] Zero or no rest frequency provided for velocity axis.
[2024-06-28 16:14:27.307Z] [CARTA] [warning] Session 2312038391: Image has no beam information.
[2024-06-28 16:14:55.359Z] [CARTA] [info] Could not find BEAMS table.
[2024-06-28 16:14:55.361Z] [CARTA] [info] [casacore] FITS card 8: CRVAL1  =                    0
[2024-06-28 16:14:55.361Z] [CARTA] [info] [casacore] Keyword value has wrong data type.
[2024-06-28 16:14:55.361Z] [CARTA] [info] [casacore] ... converted to type double.
[2024-06-28 16:14:55.361Z] [CARTA] [info] [casacore] FITS card 9: CRVAL2  =                    0
[2024-06-28 16:14:55.361Z] [CARTA] [info] [casacore] Keyword value has wrong data type.
[2024-06-28 16:14:55.361Z] [CARTA] [info] [casacore] ... converted to type double.
[2024-06-28 16:14:55.362Z] [CARTA] [info] [casacore] FITS card 10: CRVAL3  =                   20
[2024-06-28 16:14:55.362Z] [CARTA] [info] [casacore] Keyword value has wrong data type.
[2024-06-28 16:14:55.362Z] [CARTA] [info] [casacore] ... converted to type double.
[2024-06-28 16:14:55.369Z] [CARTA] [info] [casacore] FITS card 8: CRVAL1  =                    0
[2024-06-28 16:14:55.369Z] [CARTA] [info] [casacore] Keyword value has wrong data type.
[2024-06-28 16:14:55.369Z] [CARTA] [info] [casacore] ... converted to type double.
[2024-06-28 16:14:55.369Z] [CARTA] [info] [casacore] FITS card 9: CRVAL2  =                    0
[2024-06-28 16:14:55.369Z] [CARTA] [info] [casacore] Keyword value has wrong data type.
[2024-06-28 16:14:55.369Z] [CARTA] [info] [casacore] ... converted to type double.
[2024-06-28 16:14:55.369Z] [CARTA] [info] [casacore] FITS card 10: CRVAL3  =                   20
[2024-06-28 16:14:55.369Z] [CARTA] [info] [casacore] Keyword value has wrong data type.
[2024-06-28 16:14:55.369Z] [CARTA] [info] [casacore] ... converted to type double.
[2024-06-28 16:14:55.369Z] [CARTA] [info] [casacore] Header
CTYPE2  = 'DEC-TAN '
was interpreted as
CTYPE2  = 'DEC--TAN'
[2024-06-28 16:14:55.369Z] [CARTA] [info] [casacore] celfix incurred the error Inconsistent or unrecognized coordinate axis types
[2024-06-28 16:14:55.369Z] [CARTA] [info] [casacore] cylfix incurred the error Inconsistent or unrecognized coordinate axis types
[2024-06-28 16:14:55.369Z] [CARTA] [warning] [casacore] The wcs function failures are too severe to continue ...
[2024-06-28 16:14:55.369Z] [CARTA] [warning] [casacore] No proper coordinate system defined in FITS file. Using dummy linear system instead.

N.B. CARTA seems to have figured out that "DEC-TAN" should be "DEC--TAN", but it did not do the same for "RA-TAN" to "RA---TAN", which is ultimately what caused the WCS failure.