feat: Add constructive error message for Microsoft channel

[thgh]

Pull Request Template

Description

This page is hard to find: https://www.chatwoot.com/docs/self-hosted/configuration/features/email-channel/azure-app-setup
By guiding the user at the right moment, it would be a better experience for the person that configures a channel.

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality not to work as expected)
• This change requires a documentation update

How Has This Been Tested?

Not tested, I just looked up the error message when filling in correct Microsoft IMAP credentials.
This PR should be refined by someone who knows how translations are set up.

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented on my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[github-actions]

🐢 Turtley slow progress alert! This pull request has been idle for over 30 days. Can we please speed things up and either merge it or release it back into the wild?