error importing a valid gimp palette file

[Ryder17z]

Pixelorama version:
0.8.3 (snap)

OS/device including version:
Manjaro Linux 21.0.7

Issue description:

it should correctly import this file of about 730 colors.
GIMP loads it without complaints:

Steps to reproduce:
Try to import this file into Pixelorama:
color_palette.pal.txt

[OverloadedOrama]

This doesn't seem to be a valid .pal file. .pal palette files start with "JASC-PAL" as their first line (source: https://liero.nl/lierohack/docformats/other-jasc.html). This is actually a .gpl file. Changing the file extension from .pal to .gpl and then importing this to Pixelorama seems to be working fine. But if desired, we could add a way to detect an invalid .pal file and try to import it as a .gpl instead, so you wouldn't have to change the file's extension.

[Ryder17z]

ooops. but yes. automatically determine format by file header would be nice.

[novhack]

I added the palette header detection to future enhancements of the palette system. It will be tracked here #356 so I guess this issue can be closed.