LIBKML: fix error when creating a Id field of type integer

[rouault]

Fixes #11773

[coveralls]

coverage: 70.058%. first build
when pulling 4c2e68a on rouault:libkml_id_integer
into 28c687a on OSGeo:master.

[rouault]

The backport to release/3.10 failed:

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

stderr

error: could not apply 4c2e68a761... LIBKML: fix error when creating a Id field of type integer
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 autotest/ogr/ogr_libkml.py
Auto-merging ogr/ogrsf_frmts/libkml/ogrlibkmldatasource.cpp
CONFLICT (content): Merge conflict in ogr/ogrsf_frmts/libkml/ogrlibkmldatasource.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-release/3.10 release/3.10
# Navigate to the new working tree
cd .worktrees/backport-release/3.10
# Create a new branch
git switch --create backport-11796-to-release/3.10
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick 4c2e68a7617f7d6abef0eae928ba0eeed6f59dad
# Push it to GitHub
git push --set-upstream origin backport-11796-to-release/3.10
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-release/3.10

Then, create a pull request where the base branch is release/3.10 and the compare/head branch is backport-11796-to-release/3.10.

[rouault]

missed the failed backport. Oh well, that can be 3.11 material only after all