[FIX] ReadOnly Rooms permission checks

[pierre-lehnen-rc]

Proposed changes

Fixes REST API methods to properly validate if a room is readonly before sending, updating deleting or reacting to messages.

Issue(s)

Closes #17676
Closes #12534
Closes #15303

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• Improvement (non-breaking change which improves a current function)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Hotfix (a major bugfix that has to be merged asap)
• Documentation Update (if none of the other choices apply)

Checklist

• I have read the CONTRIBUTING doc
• I have signed the CLA
• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works (if applicable)
• I have added necessary documentation (if applicable)
• Any dependent changes have been merged and published in downstream modules

[pierre-lehnen-rc]

Still going to include new unit tests for those methods.