Accessibility language switch block: role="navigation"

I tested the provided patch, and it works.

Before the patch:

After the patch:

I think it's a good idea to not have the language switcher block have the navigation role attached to it as a default. Depending on how it's implemented, it could be a navigation menu on its own, or it could not.

For example, I inserted it in the header and kept the block title. This made it a navigation menu on its own.

However, if someone inserted it into the navigation menu, didn't keep the block title, and styled it to look like other items in the navigation menu, then it would be part of the larger navigation menu and not one on its own.

dcam → changed the visibility of the branch 3319633-accessibility-language-switch to hidden.

dcam → changed the visibility of the branch 11.x to hidden.

dcam → changed the visibility of the branch 3319633-language-block-role to hidden.

dcam → changed the visibility of the branch 3319633-language-block-role to active.

I converted the patch in #2 to an MR and added a test.