feat: add customizability for attachment picker ios select more photos component

[khushal87]

🎯 Goal

The goal of the PR is to add the ability to customize the attachment picker to select more photo components for iOS.

Note: This PR also removed unused docs files around the attachment picker.

🛠 Implementation details

The component can be customized using the AttachmentPickerIOSSelectMorePhotos prop in the OverlayProvider component:

Eg:

AttachmentPickerIOSSelectMorePhotos={() => {
                return (
                  <>
                    <Text>You are given selected access to the image gallery.</Text>
                    <Button onPress={iOS14RefreshGallerySelection} title='Manage' />
                  </>
                );
              }}

🎨 UI Changes

iOS

Before	After

Android

Before	After

🧪 Testing

☑️ Checklist

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

[stream-ci-bot]

🎉 This PR is included in version 5.27.0 🎉

The release is available on:

• npm package (@latest dist-tag)
• GitHub release

Your semantic-release bot 📦🚀