com.google.cloud.Identity does not support the new IAM deleted user syntax  #322

The new IAM deleted user syntax is not supported by com.google.cloud.Identity:
https://cloud.google.com/iam/docs/policies#handle-deleted-members

Environment details

1. Affects the Core library and all dependant libraries
2. OS type and version: any
3. Java version: any
4. google-cloud-core version(s): any

Steps to reproduce

1. Try to parse a deleted user string with Identity.valueOf
2. This results either to a stacktrace (1.74.0 and lower) or a DELETED identity type (1.75.0 and higher)

Code example

Identity identity = Identity.valueOf("deleted:user:[email protected]?uid=234567890123456789012");
System.out.println("type = " + identity.getType());
System.out.println("value = " + identity.getValue());

Stack trace

1.74.0 and lower

java.lang.IllegalArgumentException: Illegal identity string: "deleted:user:[email protected]?uid=234567890123456789012"

1.75.0 and higher

type = DELETED
value = user:[email protected]?uid=234567890123456789012

The "fix" is caused by an unrelated change: 24667e5

External references such as API reference guides

https://cloud.google.com/iam/docs/policies#handle-deleted-members