[mod] auth_backend:try-catch for source-read

source/overwrites/auth_backend.php

@@ -75,8 +75,15 @@ class class_auth_backend
 						]
 					)
 				);
-				$data = $realm->source->read();
-				return ($data !== null);
+				try
+				{
+					$data = $realm->source->read();
+					return ($data !== null);
+				}
+				catch (\Throwable $throwable)
+				{
+					return false;
+				}
 			}
 		}
 	}