[Module Proposal]: `avm-res-dashboard-grafana`

### Check for previous/existing GitHub issues/module proposals

- [X] I have checked for previous/existing GitHub issues/module proposals.

### Check this module doesn't already exist in the module indexes

- [X] I have checked for that this module doesn't already exist in the module indexes.

### Bicep or Terraform?

Terraform

### Module Classification?

Resource Module

### Module Name

avm-res-dashboard-grafana

### Module Details

AVM Resource Module for Azure Managed Grafana

### Do you want to be the owner of this module?

No

### Module Owner's GitHub Username (handle)

_No response_

### (Optional) Secondary Module Owner's GitHub Username (handle)

_No response_

The issue proposes a Terraform resource module named avm-res-dashboard-grafana for Azure Managed Grafana. It names no files, tests, or entry points, so start by reviewing the existing module indexes and comparable Terraform resource modules, then confirm the module scope and ownership with maintainers. Done should include an agreed implementation plan for the proposed module.

Written by the indexing model from the issue text.