Remove `-FederatedIdentityCredentials` from `New-MgServicePrincipal`

[peombwa]

Customers are not able to specify FederatedIdentityCredentials when creating service principal using New-MgServicePrincipal. We should therefore remove -FederatedIdentityCredentials parameter on New-MgServicePrincipal to mirror the API behavior.

See https://docs.microsoft.com/en-us/graph/api/resources/federatedidentitycredential?view=graph-rest-beta.

[peombwa]

As part of this task, we should also suppress *-MgServicePrincipalFederatedIdentityCredential* commands as they are internal, and are not documented by the workload - https://docs.microsoft.com/en-us/graph/api/resources/federatedidentitycredential?view=graph-rest-beta&viewFallbackFrom=graph-rest-beta.

#1384

[peombwa]

Parameter suppression is supported in AutoREST.PowerShell v3+ and not AutoREST.PowerShell v2. See https://github.com/Azure/autorest.powershell/blob/msgraph/docs/directives.md#directive-scenarios

This ask will have to wait until we release MG v2 that's generated using AutoREST.PowerShell v3. See https://github.com/microsoftgraph/msgraph-sdk-powershell/milestone/23

[peombwa]

Fixed by #1608 in v2.