AI Translate override of core translate form should be optional

MR ready, update hook maintains status quo. Changing settings rebuilds router so change takes effect immediately.

Just flagging that this is going to conflict with the solution in https://www.drupal.org/project/ai/issues/3513409 🐛 Warning: Undefined array key "#entity" in Drupal\ai_translate\Form\AiTranslateForm Active - just out of curiosity, does the issue still exist in your supported module if you use the patch from that ticket?

Ah thanks for pointing that one out! Just tested, works fine, no merge conflict.

Default: both TMGMT & AI Translate show
Untick new box: Only TMGMT interface is shown