[Backport #1974 to 5.x] Remove obsolete dependency on ext-json

[github-actions]

Automated backport of #1974 to branch 5.x.

Do not modify this pull request.

Fixes #1973

[github-actions]

Please cherry-pick the changes locally and resolve any conflicts.

git fetch origin backport-1974-to-5.x
git worktree add --checkout .worktree/backport-1974-to-5.x backport-1974-to-5.x
cd .worktree/backport-1974-to-5.x
git reset --hard HEAD^
git cherry-pick -x 6ffe4691b54df6f291ad63ff3345c473621c85e6
git push --force-with-lease