Preserving metadata during upscaling

[panchi64]

Related to #6291

Implements metadata preservation during the upscaling process invocation by:

• Creating a copy of the original metadata before the upscaling process begins to ensure the original data remains unaltered.
• Updating the upscaled image's metadata once upscaling is complete.
• Ensuring the updated metadata is passed along when saving the upscaled image.

[panchi64]

I haven't had the time to fully test this "fix" with lots of different image sizes (although I expect it should work the same) but will do so once I have the chance today.

Should I create a test file for this metadata copying as well?
I assume that this isn't the only place that the metadata copying would be useful.