[Feature]: Remove-AzRoleAssignment : Remove classical Administrator

### Description of the new feature

### Description
When using the command "Remove-AzRoleAssignment" unable to delete "Classical Administrator"

```
PS > $role = Get-AzRoleAssignment -IncludeClassicAdministrators | Where-Object {$_.RoleDefinitionName -like "*ServiceAdministrator*"}
PS > Remove-AzRoleAssignment -SignInName $role.SignInName -RoleDefinitionName "ServiceAdministrator" -Scope $role.Scope
```
### Error output
```
Remove-AzRoleAssignment : The provided information does not map to a role assignment.
Au caractère Ligne:1 : 1
+ Remove-AzRoleAssignment -SignInName $role.SignInName -RoleDefinitionN ...
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ CategoryInfo : CloseError : (:) [Remove-AzRoleAssignment], KeyNotFoundException
+ FullyQualifiedErrorId : Microsoft.Azure.Commands.Resources.RemoveAzureRoleAssignmentCommand
```

### Proposed implementation details (optional)

Like the cmdlet Get-AzRoleAssignment include a parameter -IncludeClassicAdministrators to be able to delete Classical Admin

```
Get-AzRoleAssignment -IncludeClassicAdministrators

Remove-AzRoleAssignment -SignInName $SignInName -RoleDefinitionName "ServiceAdministrator" -Scope $Scope -IncludeClassicAdministrators
```