[WIP] Improve Templates for Slack, GChat, and MSTeams

[Siddhanttimeline]

Describe your changes:

Fixes: #https://github.com/open-metadata/OpenMetadata/issues/17717 Creating new templates for alerts and notifications for Slack, GChat and MSTeams.

1. For DQ alerts
2. For destination tests
3. For general ChangeEvent alerts

Type of change:

• [ ] Bug fix
• [x] Improvement
• [ ] New feature
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)
• [ ] Documentation

Checklist:

• [x] I have read the CONTRIBUTING document.
• [ ] My PR title is Fixes <issue-number>: <short explanation>
• [x] I have commented on my code, particularly in hard-to-understand areas.
• [ ] For JSON Schema changes: I updated the migration scripts or explained why it is not needed.