[FIX] Permissions to edit livechat when the user is a livechat-agent

[reinaldonetof]

Proposed changes

Last month the way that the API permit a user to edit the livechat was changed to 'edit-omnichannel-contact', because that was occurring a bug when the agent wants to edit something.

Issue(s)

The same agent could edit a livechat on the web, but on the mobile app couldn't

How to test or reproduce

1 - Activate Omnicahnnel -> https://docs.rocket.chat/guides/omnichannel-guides/omnichannel-admins-guide
3 - Start a new chat through Livechat https://multiverse.rocket.chat/livechat
4 - Go to Omnichannel Queue (Mobile)
5 - Open an incoming chat
6 - Click on the title
7- At Actions screen click on name of the user
8 - Will appear the edit button

Screenshots

Before	After

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

[AlexAlexandre]

LGTM