Add tooltip text to the close button of Modals.

[luniki]

Fixes #1218.

[github-actions]

Use docker or podman to test this pull request locally.

Run test server using develop.opencast.org as backend:

podman run --rm -it -p 127.0.0.1:3000:3000 ghcr.io/opencast/opencast-admin-interface:pr-1220

Specify a different backend like stable.opencast.org:

podman run --rm -it -p 127.0.0.1:3000:3000 -e PROXY_TARGET=https://stable.opencast.org ghcr.io/opencast/opencast-admin-interface:pr-1220

It may take a few seconds for the interface to spin up.
It will then be available at http://127.0.0.1:3000.
For more options you can pass on to the proxy, take a look at the README.md.

[github-actions]

This pull request is deployed at test.admin-interface.opencast.org/1220/2025-05-13_11-42-21/ .
It might take a few minutes for it to become available.

[NadiaUoM]

Instead of hard coding the CLOSE text directly can you please read it from lang-en_US.json file. If you do so internalization can be possible if needed....

[lkiesow]

Instead of hard coding the CLOSE text directly can you please read it from lang-en_US.json file. If you do so internalization can be possible if needed....

Internationalization already works. It's not actually hard-coded. That's the translation string. So, I think we can ignore that complaint.

However, looking at the placement of the tooltip, that doesn't seem right. The placement is far too low:

[github-actions]

This pull request has conflicts ☹
Please resolve those so we can review the pull request.
Thanks.