Course Builder Lesson Content fixes

[brianhogg]

Description

• Correctly flag the lesson content as edited within the Course Builder
• Detect if edited with the block editor or certain page builders, and show the message at that time

Fixes #3360

How has this been tested?

Manually

Screenshots

Checklist:

• This PR requires and contains at least one changelog file.
• My code has been tested.
• My code passes all existing automated tests.
• My code follows the LifterLMS Coding & Documentation Standards.