fix: remove redundant error messages in admin functions (#7953)

Closes #7938

Signed-off-by: yxrxy <yxrxytrigger@gmail.com>

src/common/function/src/admin/flush_compact_region.rs

@@ -128,7 +128,7 @@ mod tests {
                     };
                     let result = f.invoke_async_with_args(func_args).await.unwrap_err();
                     assert_eq!(
-                        "Execution error: Handler error: Missing TableMutationHandler, not expected",
+                        "Execution error: Missing TableMutationHandler, not expected",
                         result.to_string()
                     );
                 }

src/common/function/src/admin/flush_compact_table.rs

@@ -355,7 +355,7 @@ mod tests {
                     };
                     let result = f.invoke_async_with_args(func_args).await.unwrap_err();
                     assert_eq!(
-                        "Execution error: Handler error: Missing TableMutationHandler, not expected",
+                        "Execution error: Missing TableMutationHandler, not expected",
                         result.to_string()
                     );
                 }

src/common/function/src/admin/migrate_region.rs

@@ -173,7 +173,7 @@ mod tests {
         };
         let result = f.invoke_async_with_args(func_args).await.unwrap_err();
         assert_eq!(
-            "Execution error: Handler error: Missing ProcedureServiceHandler, not expected",
+            "Execution error: Missing ProcedureServiceHandler, not expected",
             result.to_string()
         );
     }

src/common/function/src/flush_flow.rs

@@ -149,7 +149,7 @@ mod test {
 
         let result = f.invoke_async_with_args(func_args).await.unwrap_err();
         assert_eq!(
-            "Execution error: Handler error: Missing FlowServiceHandler, not expected",
+            "Execution error: Missing FlowServiceHandler, not expected",
             result.to_string()
         );
     }