feat: support file_size config in file and image upload

[khushal87]

🎯 Goal

The goal of the PR is to support file_size image and file config such the file size exceeding the limit cannot be uploaded. The limit can be controlled or set from the dashboard. The default is 100 MB in the SDK.

There are a couple of improvements to how app settings are fetched on mounted and improving the code of existing file config.

🛠 Implementation details

🎨 UI Changes

iOS

Before	After

Android

Before	After

🧪 Testing

☑️ Checklist

• [x] I have signed the Stream CLA (required)
• [x] PR targets the develop branch
• [ ] Documentation is updated
• [x] New code is tested in main example apps, including all possible scenarios
  • [x] SampleApp iOS and Android
  • [x] Expo iOS and Android