refactor: Port content-scripts-injector to TypeScript (#17012)

typings/internal-ambient.d.ts

@@ -26,6 +26,13 @@ declare namespace NodeJS {
     atomBinding(name: 'command_line'): Electron.CommandLine;
     log: NodeJS.WriteStream['write'];
     activateUvLoop(): void;
+
+    // Additional methods
+    getRenderProcessPreferences(): Array<Electron.RendererProcessPreference> | null;
+
+    // Additional events
+    once(event: 'document-start', listener: () => any): this;
+    once(event: 'document-end', listener: () => any): this;
   }
 }