Don't compile node_modules by default

To make a first time setup of the compiler truly config-less, default to
not compiling node_modules unless a user provided `sources` (advanced
option) is provided

ghstack-source-id: b0798052404d772ce6ee471e577699d4b0871d56
Pull Request resolved: https://github.com/facebook/react-forget/pull/2919

compiler/packages/babel-plugin-react-forget/src/Entrypoint/Options.ts

@@ -185,6 +185,9 @@ export const defaultOptions: PluginOptions = {
   eslintSuppressionRules: null,
   flowSuppressions: false,
   ignoreUseNoForget: false,
+  sources: (filename) => {
+    return filename.indexOf("node_modules") === -1;
+  },
 } as const;
 
 export function parsePluginOptions(obj: unknown): PluginOptions {