Project Translation considers descriptions of Value Map Widget

[signedav]

Value Map descriptions can now be translated as well.

This loaded with EN settings	...becomes this loaded with DE settings

The values are of course the same.

This fixes #56089

Additionally I included missing tests for the Value Relation value translation.
The ts file is committed as well, so the tests can be extended in future with low effort.

This handles only value maps stored as QLists (means after this implementation #6091 and > 3.4)

[github-actions]

🪟 Windows builds

Download Windows builds of this PR for testing.
Debug symbols for this build are available here.
(Built from commit 8a98242)

🪟 Windows Qt6 builds

Download Windows Qt6 builds of this PR for testing.
(Built from commit 8a98242)

[3nids]

LGTM!

[signedav]

Beside using QList consequently I added this line. Otherwise it would just had returned an empty list, but with this it's cleaner...

[signedav]

Thanks @3nids

[qgis-bot]

The backport to queued_ltr_backports failed:

The process '/usr/bin/git' failed with exit code 1

stderr

error: could not apply 5d63c80a292... ValueMap description are translated in project translation process. Fixes #56089
hint: After resolving the conflicts, mark them with
hint: "git add/rm <pathspec>", then run
hint: "git cherry-pick --continue".
hint: You can instead skip this commit with "git cherry-pick --skip".
hint: To abort and get back to the state before "git cherry-pick",
hint: run "git cherry-pick --abort".
hint: Disable this message with "git config set advice.mergeConflict false"

stdout

Auto-merging src/core/project/qgsproject.cpp
Auto-merging src/core/vector/qgsvectorlayer.cpp
Auto-merging src/gui/vector/qgsattributesformproperties.cpp
CONFLICT (content): Merge conflict in src/gui/vector/qgsattributesformproperties.cpp

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-queued_ltr_backports queued_ltr_backports
# Navigate to the new working tree
cd .worktrees/backport-queued_ltr_backports
# Create a new branch
git switch --create backport-60744-to-queued_ltr_backports
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick 5d63c80a2921b1016bb5ee0d3d5b80522f48aa0c,864543becddf470d2d375e776d61321c7b4e8a95,529d85b3d95170e2ef8a1495c6091650335e0bb3,dcab0217709aa4e21cc7a8229f173945d4da07b5,8a982428f40e7ea95568037241cf2a17ad2ed004
# Push it to GitHub
git push --set-upstream origin backport-60744-to-queued_ltr_backports
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-queued_ltr_backports

Then, create a pull request where the base branch is queued_ltr_backports and the compare/head branch is backport-60744-to-queued_ltr_backports.