Prefer FOUNDATION_EXPORT for Analytics constants

### Description

See `FIRParameterNames.h`. Likely non-breaking, but less risky to experiment during major version release.

### Reproducing the issue

_No response_

### Firebase SDK Version

12.0.0

### Xcode Version

16.2

### Installation Method

N/A

### Firebase Product(s)

Analytics

### Targeted Platforms

All

### Relevant Log Output

```shell

```

### 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!

```