Fix error display

Author: MalloryWittwer

src/imaging_server_kit/core/errors.py

@@ -89,7 +89,7 @@ def __init__(
     ):
         self.message = message + f"{algorithm=}"
         if error is not None:
-            self.message = self.message + ", Error: {error}"
+            self.message = self.message + f", Error: {error}"
         super().__init__(self.message)