Accessibility: Add title attribute for iframe element

Here's a simple patch for starters. Trying to use the media entity label for the title and providing a default value "Video" (translatable).
Also, noticed some problems in tests (unrelated) and tried to fix them too.

Thanks for posting the issue! I happen to know of a solution that is already in use: https://github.com/Tampere/tampere-fi/blob/main/patches/media_entity_dre...

We could combine these approaches maybe?

Oh, you were fast! Nice that you have taken into account the translations too, I completely forgot about them.
I can test your approach too and provide a new patch.

Ok, here's another try. I tried to combine your patch with mine. Hopefully I didn't mess up something there...

And by the way, how to use the latest version in tests? Now it seems only "media_entity_dreambroker 8.x-1.x-dev" is available in the "Test with" drop-down?

Thanks for the patch. The testing configuration is not up to date in this project, we should add a gitlab setup to get access to testing again.