fix: image and paste insert

[KristinAoki]

Description

This PR fixes a bug introduced in #480 where content that is inserted like pasting and adding images always inserted it at the beginning of the block, not where the cursor was last placed. This bug appeared because the content was updated before the insert happened so the cursor was moved to the beginning of the block for the new content. This PR fixes the update function to only update the content when the content is actually changed, not on every editor click.

Supporting Information

JIRA Ticket: TNL-11663 🔒

Testing

1. Open a tab for each page that uses the visual editors
   • text editor
   • problem editor
   • course updates
2. Copy and paste text into various parts of the editor
   • in the middle of a sentence
   • end of block
   • highlight and replace
3. Add an image
   • in the middle of a sentence
   • end of block
   • highlight and replace
4. Confirm that each of these additions add content i the expected location

[codecov]

Codecov Report

Attention: Patch coverage is 92.30769% with 2 lines in your changes missing coverage. Please review.

Project coverage is 88.91%. Comparing base (2678234) to head (6b12726).

Files	Patch %	Lines
...rc/editors/sharedComponents/TinyMceWidget/hooks.js	92.00%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #490      +/-   ##
==========================================
+ Coverage   88.86%   88.91%   +0.05%     
==========================================
  Files         248      248              
  Lines        4535     4538       +3     
  Branches      934      937       +3     
==========================================
+ Hits         4030     4035       +5     
+ Misses        474      470       -4     
- Partials       31       33       +2     

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