Update and fix Facebook signin integration in FirebaseAuth Sample and Tests

### Description

Auth nightly integration tests fail six straight days - #10738

- Update version from 12.x to latest (currently 15.x) in the [Podfile](https://github.com/firebase/firebase-ios-sdk/blob/master/FirebaseAuth/Tests/Sample/Podfile)
- Update Sample to build with latest Facebook SDK
- Restore tests disabled in #10753

### Reproducing the issue

Run the nightly integration tests

### Firebase SDK Version

10.4.0

### Xcode Version

14.2

### Installation Method

CocoaPods

### Firebase Product(s)

Authentication

### Targeted Platforms

iOS

### Relevant Log Output

```shell
2023-01-30 09:26:21.409010+0000 AuthSample[36042:101880] Creating Facebook account finished with error: Error Domain=com.google.HTTPStatus Code=400 "(null)" UserInfo={data={length = 164, bytes = 0x7b226572 726f7222 3a7b226d 65737361 ... 76654f71 78227d7d }, data_content_type=application/json; charset=UTF-8}
/Users/runner/work/firebase-ios-sdk/firebase-ios-sdk/FirebaseAuth/Tests/Sample/ApiTests/FacebookAuthTests.m:150: error: -[FacebookAuthTests testSignInWithFaceboook] : Asynchronous wait failed: Exceeded timeout of 10 seconds, with unfulfilled expectations: "Creating Facebook account finished.".
```

### If using Swift Package Manager, the project's Package.resolved

Expand Package.resolved snippet

```json

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```

### If using CocoaPods, the project's Podfile.lock

Expand Podfile.lock snippet

```yml

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```