Fix D&D GPKG from browser

[elpaso]

Fixes #43129

[elpaso]

@agiudiceandrea can you please test this PR?

[agiudiceandrea]

@elpaso both the main issue #43129 and the additional issue #43129 (comment) are fixed with this PR (anyway the "Invalid Layer" critical error message still show up).

Thank you.

[qgis-bot]

The backport to queued_ltr_backports failed:

The process '/usr/bin/git' failed with exit code 128

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-43436-to-queued_ltr_backports
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick 3de9f49427e279bf6302b74db4e475572b0230a3
# Push it to GitHub
git push --set-upstream origin backport-43436-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-43436-to-queued_ltr_backports.