feat(API): Add an endpoint to check for existance of notification ids

[nickvergessen]

• The endpoint can be used by the mobile clients to confirm that a notification still exists (even when not in the last 25 items, or whether the push notification should be removed. For the beginning a maximum of 200 items can be checked in 1 go, if more are supplied a 400 Bad Request is returned

[github-actions]

🐢 Performance warning.
It looks like the query count of the integration tests increased with this PR.
Database query count is now 10026 was 9500 (+5.53%)
Please check your code again. If you added a new test this can be expected and the base value in tests/Integration/base-query-count.txt can be increased.

[github-actions]

🐢 Performance warning.
It looks like the query count of the integration tests increased with this PR.
Database query count is now 10026 was 9500 (+5.53%)
Please check your code again. If you added a new test this can be expected and the base value in tests/Integration/base-query-count.txt can be increased.

[SystemKeeper]

Tested and works 👍

[nickvergessen]

/backport to stable26

[backportbot-nextcloud]

The backport to stable26 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable26
git pull origin/stable26

# Create the new backport branch
git checkout -b fix/foo-stable26

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts. Resolve them.
git cherry-pick abc123

# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable26

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport