feat: Encrypt file descriptions on E2EE rooms

[diegolmello]

Proposed changes

Self explanatory. Added some functions in order to encrypt description on sendFileMessage

Issue(s)

Related to #31840

How to test or reproduce

Note: Depends on #31840, so make sure to test running that branch.

Encrypt

• Send a file with a description
• It should be encrypted

Decrypt

• Send a file with a description on web
• Mobile should decrypt it

Screenshots

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)
• 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

Further comments

CORE-105