MM-17006: An http 404 response code is returned when deleting a non existent plugin (#11631)

Automatic Merge

app/plugin_statuses.go

@@ -28,7 +28,7 @@ func (a *App) GetPluginStatus(id string) (*model.PluginStatus, *model.AppError)
 			return status, nil
 		}
 	}
-	return nil, model.NewAppError("GetPluginStatus", "app.plugin.not_installed.app_error", nil, "", http.StatusBadRequest)
+	return nil, model.NewAppError("GetPluginStatus", "app.plugin.not_installed.app_error", nil, "", http.StatusNotFound)
 }
 
 // GetPluginStatuses returns the status for plugins installed on this server.