Bug: RoleAssignmentProperties.DelegatedManagedIdentityResourceId has wrong type

[theunrepentantgeek]

Describe the bug

As discussed in #3772 the propertyRoleAssignmentProperties.DelegatedManagedIdentityResourceId from the authorization group has the wrong type.

Unlike the other groups identified in that issue, there is no newer version of authorization to import, so we can't fix this with a non-breaking change.

What should we do?

[matthchr]

I wonder if there's any way for us to know how much usage this property has today? I think that's a pretty esoteric property... we could take a break but if would be good to know it had no usage (or very low usage) before we did. Might be able to check ASI and see what it does.

OTOH we could live with it as it is, under the philosophy "better to not break users". Since nobody is complaining about this right now it may not be a huge issue?

Thoughts?