Errors: Make errors the same in dev as prod (#77366)

When running in dev mode, error messages would contain an additional "error" property alongside "message". Since this causes confusion, that has been removed and now error messages are the same both modes (using "message").

pkg/api/metrics_test.go

@@ -162,7 +162,7 @@ func TestAPIEndpoint_Metrics_PluginDecryptionFailure(t *testing.T) {
 		var resObj secretsErrorResponseBody
 		err = json.Unmarshal(buf.Bytes(), &resObj)
 		require.NoError(t, err)
-		require.Equal(t, "unknown error", resObj.Error)
+		require.Equal(t, "", resObj.Error)
 		require.Contains(t, resObj.Message, "Secrets Plugin error:")
 	})
 }
@@ -264,12 +264,12 @@ func TestDataSourceQueryError(t *testing.T) {
 		{
 			request:        reqDatasourceByUidNotFound,
 			expectedStatus: http.StatusNotFound,
-			expectedBody:   `{"error":"data source not found","message":"Data source not found","traceID":""}`,
+			expectedBody:   `{"message":"Data source not found","traceID":""}`,
 		},
 		{
 			request:        reqDatasourceByIdNotFound,
 			expectedStatus: http.StatusNotFound,
-			expectedBody:   `{"error":"data source not found","message":"Data source not found","traceID":""}`,
+			expectedBody:   `{"message":"Data source not found","traceID":""}`,
 		},
 	}