fix: allow user self deletion (#9828)

# Which Problems Are Solved

Currently, users can't delete themselves using the V2 RemoveUser API
because of the redunant API middleware permission check.

On main, using a machine user PAT to delete the same machine user:

```bash
grpcurl -plaintext -H "Authorization: Bearer ${ZITADEL_ACCESS_TOKEN}" -d '{"userId": "318838604669387137"}' localhost:8080 zitadel.user.v2.UserService.DeleteUser
ERROR:
  Code: NotFound
  Message: membership not found (AUTHZ-cdgFk)
  Details:
  1)	{
    	  "@type": "type.googleapis.com/zitadel.v1.ErrorDetail",
    	  "id": "AUTHZ-cdgFk",
    	  "message": "membership not found"
    	}
```

Same on this PRs branch:

```bash
grpcurl -plaintext -H "Authorization: Bearer ${ZITADEL_ACCESS_TOKEN}" -d '{"userId": "318838604669387137"}' localhost:8080 zitadel.user.v2.UserService.DeleteUser
{
  "details": {
    "sequence": "3",
    "changeDate": "2025-05-06T13:44:54.349048Z",
    "resourceOwner": "318838541083804033"
  }
}
```

Repeated call
```bash
grpcurl -plaintext -H "Authorization: Bearer ${ZITADEL_ACCESS_TOKEN}" -d '{"userId": "318838604669387137"}' localhost:8080 zitadel.user.v2.UserService.DeleteUser
ERROR:
  Code: Unauthenticated
  Message: Errors.Token.Invalid (AUTH-7fs1e)
  Details:
  1)	{
    	  "@type": "type.googleapis.com/zitadel.v1.ErrorDetail",
    	  "id": "AUTH-7fs1e",
    	  "message": "Errors.Token.Invalid"
    	}
```

# How the Problems Are Solved

The middleware permission check is disabled and the
domain.PermissionCheck is used exclusively.

# Additional Changes

A new type command.PermissionCheck allows to optionally accept a
permission check for commands, so APIs with middleware permission checks
can omit redundant permission checks by passing nil while APIs without
middleware permission checks can pass one to the command.

# Additional Context

This is a subtask of #9763

---------

Co-authored-by: Livio Spring <livio.a@gmail.com>

internal/command/user_v2_invite_test.go

@@ -323,7 +323,21 @@ func TestCommands_ResendInviteCode(t *testing.T) {
 			"missing permission",
 			fields{
 				eventstore: expectEventstore(
-					expectFilter(),
+					expectFilter(
+						eventFromEventPusher(
+							user.NewHumanAddedEvent(context.Background(),
+								&user.NewAggregate("userID", "org1").Aggregate,
+								"username", "firstName",
+								"lastName",
+								"nickName",
+								"displayName",
+								language.Afrikaans,
+								domain.GenderUnspecified,
+								"email",
+								false,
+							),
+						),
+					),
 				),
 				checkPermission: newMockPermissionCheckNotAllowed(),
 			},