Setitngs: button to reset Android SDK path to default

Summary: Added button to reset Android SDK path to default + fixed default SDK path on Windows which I introduced in a previous diff and which before might be wrongly resolved to roaming data instead of local data folder

Reviewed By: jknoxville

Differential Revision: D19498899

fbshipit-source-id: e10865b528f55ea6b56873bdf9369c4b60dca89f

__mocks__/electron.tsx

@@ -13,6 +13,7 @@ module.exports = {
       env: {},
     },
     app: {
+      getPath: (path: string) => `/${path}`,
       getAppPath: process.cwd,
       getVersion: () => '0.9.99',
       relaunch: () => {},