Credential modification should check type, not just index. (#35074)

Credential indices are per-type, so we should be checking both when locating the
credential to be modified.

This is a backport of #34841 to the 1.2 branch.

Author: bzbarsky-apple

src/app/clusters/door-lock-server/door-lock-server.cpp

@@ -2250,8 +2250,9 @@ DlStatus DoorLockServer::modifyCredentialForUser(chip::EndpointId endpointId, ch
 
     for (size_t i = 0; i < user.credentials.size(); ++i)
     {
-        // appclusters, 5.2.4.40: user should already be associated with given credentialIndex
-        if (user.credentials.data()[i].credentialIndex == credential.credentialIndex)
+        // appclusters, 5.2.4.40: user should already be associated with given credential
+        if (user.credentials[i].credentialType == credential.credentialType &&
+            user.credentials[i].credentialIndex == credential.credentialIndex)
         {
             chip::Platform::ScopedMemoryBuffer<CredentialStruct> newCredentials;
             if (!newCredentials.Alloc(user.credentials.size()))
@@ -2295,7 +2296,7 @@ DlStatus DoorLockServer::modifyCredentialForUser(chip::EndpointId endpointId, ch
         }
     }
 
-    // appclusters, 5.2.4.40: if user is not associated with credential index we should return INVALID_COMMAND
+    // appclusters, 5.2.4.40: if user is not associated with the given credential we should return INVALID_COMMAND
     ChipLogProgress(Zcl,
                     "[ModifyUserCredential] Unable to modify user credential: user is not associated with credential index "
                     "[endpointId=%d,userIndex=%d,credentialIndex=%d]",