FAL-984 port recent xss patches to common juniper branch

[samuelallan72]

Sandbox:

• LMS: https://fal-984-xss-fixes.opencraft.hosting/
• Studio: https://studio.fal-984-xss-fixes.opencraft.hosting/

Test instructions:

• verify that the changes match the patches (these all applied cleanly):
  • https://discuss.openedx.org/t/security-im-patch-for-xss-fixes-7/4198
  • https://discuss.openedx.org/t/security-im-patch-for-xss-fixes-8/4231
  • https://discuss.openedx.org/t/security-im-patch-for-xss-fixes-9/4297
• verify that the notes xss fix is not required for this branch: edx@f132471 | https://discuss.openedx.org/t/security-patch-for-xss-fixes-on-learner-notes-feature/4241
• verify that an instance with this branch provisions successfully (check the sandbox)
• browse through the files changed and run a quick check of the associated functionality on the sandbox

Author notes:

• I directly applied and committed the patches because the patches were applied in many small commits upstream (according to the ticket), so this is cleaner.

Reviewers:

• @eLRuLL
• @pomegranited
  (as firefighters)

[eLRuLL]

@swalladge LGTM 👍

• I read through the code and made sure changes belong to the applied patches
• I followed test instructions successfully
• I checked this is working correctly in a sandbox instance