FIAM `tests` workflow job has UI tests that flake on CI

### Description

Disabled in #14758 to make nightlies less noisy

### Reproducing the issue

_No response_

### Firebase SDK Version

11.12

### Xcode Version

16.2

### Installation Method

Swift Package Manager

### Firebase Product(s)

In-App Messaging

### Targeted Platforms

iOS

### 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!

```