[Feature request] `az ad app permission admin-consent`: Migrate `https://main.iam.ad.ext.azure.com/` to Microsoft Graph

**Related command**
`az ad app permission admin-consent`

**Is your feature request related to a problem? Please describe.**
`az ad app permission admin-consent` internally calls `https://main.iam.ad.ext.azure.com/` endpoint:

https://github.com/Azure/azure-cli/blob/38eaebb6936a32be13e2c4afba8e600ce9c91513/src/azure-cli/azure/cli/command_modules/role/custom.py#L959

This endpoint has several limitations:

1. This endpoint is now deprecated
2. It can only be called by a user, not a service principal.
3. It fails in Cloud Shell, because `https://main.iam.ad.ext.azure.com/` is not a resource supported by Cloud Shell (#8912, #14230)
4. It doesn't support sovereign clouds (#9942)

**Describe the solution you'd like**
Migrate `https://main.iam.ad.ext.azure.com/` to Microsoft Graph.

**Describe alternatives you've considered**
Remove `az ad app permission admin-consent` and replace it with fine-grained `az ad app permission grant` and https://github.com/Azure/azure-cli/issues/22768.

**Additional context**