Fixes #1687. Stretched Grid checkpoint attributes should be in degrees

[mathomp4]

Description

Per #1687 from @LiamBindle, our checkpoints for stretched grid checkpoints are outputting TARGET_LON and TARGET_LAT in radians and not degrees. This PR should fix that.

Related Issue

Closes #1687

Motivation and Context

Solves an issue from our GCHP friends.

How Has This Been Tested?

I compiled and ran it with GEOSgcm. It is trivially zero-diff for GEOS as we do not (yet) use stretched grid. I suppose the real test will be when GCHP can test it.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Trivial change (affects only documentation or cleanup)

Checklist:

• I have tested this change with a run of GEOSgcm (if non-trivial)
• I have added one of the required labels (0 diff, 0 diff trivial, 0 diff structural, non 0-diff)
• I have updated the CHANGELOG.md accordingly following the style of Keep a Changelog

[tclune]

See inline comments.

[tclune]

Thanks.

[lizziel]

Sorry I was unaware of this issue and fix before today. I just tested it and it still gives problems. I will follow-up at #1977