Fix Performance unit tests on Xcode 15+

### Description

The Performance unit tests should run from Xcode 15

### Reproducing the issue

`bundle exec pod gen FirebasePerformance.podspec --auto-open --local-sources=./ --platforms=ios`
Select the unit test scheme and tes:


### Firebase SDK Version

10.16.0

### Xcode Version

15

### Installation Method

CocoaPods

### Firebase Product(s)

Performance

### Targeted Platforms

iOS

### Relevant Log Output

_No response_

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

Expand Package.resolved snippet

```json

Replace this line with the contents of your Package.resolved.

```

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

Expand Podfile.lock snippet

```yml

Replace this line with the contents of your Podfile.lock!

```