Plugin download failure is not an error

Summary: Plugin download failure is typical a transient error, no need to trigger monitoring for that

Reviewed By: ivanmisuno

Differential Revision: D43118116

fbshipit-source-id: 0cd0f87f0ed6123adcba28139308ecea92b1b508

desktop/flipper-server-core/src/plugins/PluginManager.tsx

@@ -185,7 +185,7 @@ export class PluginManager {
         return await installPluginFromFile(tmpFile);
       }
     } catch (error) {
-      console.error(
+      console.warn(
         `Failed to download plugin "${title}" v${version} from "${downloadUrl}" to "${installationDir}".`,
         error,
       );