Use the images upload menu when an image dropped

[MisRob]

Description

Do not trigger image upload and do not display an image in the content area of the markdown editor immediately after drop. Instead, open the images upload menu with the image and let the menu handle the rest of the upload and insert process.

Issue Addressed

Closes#2177

Steps to Test

• Drop an image into the markdown editor content area

Checklist

• Is the code clean and well-commented?
• Has the docs label been added if this introduces a change that needs to be updated in the user docs?
• Has the CHANGELOG label been added to this pull request? Items with this label will be added to the CHANGELOG at a later time
• Are there tests for this change?
• Are all user-facing strings translated properly (if applicable)?
• Has the notranslate class been added to elements that shouldn't be translated by Google Chrome's automatic translation feature (e.g. icons, user-generated text)?
• Are all UI components LTR and RTL compliant (if applicable)?
• Are views organized into pages, components, and layouts directories as described in the docs?
• Are there any new ways this uses user data that needs to be factored into our Privacy Policy?
• Are there any new interactions that need to be added to the QA Sheet?
• Are there opportunities for using Google Analytics here (if applicable)?
• If the Pipfile has been changed, is the updated Pipfile.lock file also included in this PR?
• Are the migrations safe for a large db (if applicable)?

[MisRob]

Regarding dropping more images than one, there's an issue - please see the last comment.

[codecov]

Codecov Report

Merging #2332 into develop will not change coverage.
The diff coverage is n/a.

@@ Coverage Diff @@## develop #2332 +/- ##
========================================
Coverage 81.46% 81.46% ========================================
Files 293 293 Lines 14106 14106 ========================================
Hits 11491 11491 Misses 2615 2615 

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