Add logging and fallback for failing vpnless requests

Summary:
If a requests fails due to lack of allow-listing or other incompatibilities, we will now fall back to VPN mode while logging an error that will hopefully end up at the plugin owner.

For this, there's a new `vpnMode` option on every request that can also be used to enforce a particular type.

There's a lot of verbose logging that's turned off by default but very handy when debugging. Also potentially useful for plugin authors that are looking into request issues.

Reviewed By: lblasa

Differential Revision: D49023365

fbshipit-source-id: 755393063e379587feda9ae13973877780a1d987

desktop/flipper-server-core/src/fb-stubs/internRequests.tsx

@@ -21,6 +21,7 @@ export async function internGraphPOSTAPIRequest(
     timeout?: number;
     internGraphUrl?: string;
     headers?: Record<string, string | number | boolean>;
+    vpnMode?: 'vpn' | 'vpnless';
   },
   token: string,
 ): Promise<GraphResponse> {
@@ -36,6 +37,7 @@ export async function internGraphGETAPIRequest(
     timeout?: number;
     internGraphUrl?: string;
     headers?: Record<string, string | number | boolean>;
+    vpnMode?: 'vpn' | 'vpnless';
   },
   token: string,
 ): Promise<GraphResponse> {