* Updates the sign-in methods on Swift Sample
Updates the sign-in, reauth and link with credential methods on Swift Sample to use the recommended Auth result paradigm.
* adds missing space after {
* addresses comments
* Update Auth version to 4.3.0
* Revert "Removes user meta from public API (#308)"
This reverts commit 1602391bf8.
* Revert "Removes metadata from swift sample (#318)"
This reverts commit 804ff523a2.