Az.Compute Update-AzVM/VMSS should accept userAssignedIdentities dictionary as parameter
When assigning a user assigned identity to a VM/VMSS, the Az.Compute module command Update-AzVM/VMSS accepts the array IdentityIds but not the new parameter UserAssignedIdentities dictionary. Instead the command converts the IdentityIds array into the UserAssignedIdentities dictionary.
This is an inconvenience because a VM/VMSS can have up to 1000 identities. When updating the VM/VMSS, it is much more succinct to use a dictionary because then the user only needs to include the individual user assigned identities they want to add/remove. It also matches the pattern that already exists when they look at the identity information on the VM/VMSS.
With the IdentityIds array they need to include every single identity that is on the VM/VMSS, exclude the ones they want to remove, and include the new identities they want to add.