Handle LM blocks being used outside LM templates

[Imran92]

Steps to Reproduce

1. Activate a block theme
2. Go to Appearance -> Editor
3. Open any template other than the LM template
4. Try to find a LM specific block (Like 'Lesson actions') block

What I Expected

Either not be able to find the LM blocks in non-LM templates or even if we add them in the right context, for example, in a non-LM Lesson template, it shouldn't look broken

What Happened Instead

We could add them in all templates and they looked broken after being added in non-LM lesson templates

PHP / WordPress / Sensei LMS version

8.1, 6.3, 4.16.1

Browser / OS version

Chrome, Opera

6662212-zd-a8c

[github-actions[bot]]

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