Restore exception handling for item accessibility problems.

Shouldn't this fix galaxyproject#10309? This way the exception falls through the object collecting exceptions and reporting them back instead of short circuiting the workflow scheduling stuff.

lib/galaxy/tools/__init__.py

@@ -1654,7 +1654,7 @@ def handle_single_execution(self, trans, rerun_remap_job_id, execution_slice, hi
             if len(rval) == 4:
                 execution_slice.datasets_to_persist = rval[2]
                 execution_slice.history = rval[3]
-        except (webob.exc.HTTPFound, exceptions.MessageException) as e:
+        except webob.exc.HTTPFound as e:
             # if it's a webob redirect exception, pass it up the stack
             raise e
         except ToolInputsNotReadyException as e: