Change AttachmentPickerAction from sealed interface to interface

[VelikovPetar]

🎯 Goal

Change AttachmentPickerAction from sealed interface to interface to allow custom implementations.
Resolves: https://linear.app/stream/issue/AND-758/expose-attachmentpickeraction-interface-for-custom-actions

🛠 Implementation details

Change AttachmentPickerAction from sealed interface to interface

🎨 UI Changes

NA

🧪 Testing

Create a class which implements the AttachmentPickerAction to verify that it is now extensible outside its own module.

[github-actions]

SDK Size Comparison 📏

SDK	Before	After	Difference	Status
stream-chat-android-client	3.23 MB	3.23 MB	0.00 MB	🟢
stream-chat-android-offline	3.45 MB	3.45 MB	0.00 MB	🟢
stream-chat-android-ui-components	10.54 MB	10.54 MB	0.00 MB	🟢
stream-chat-android-compose	12.75 MB	12.75 MB	0.00 MB	🟢

[Copilot]

Pull Request Overview

This PR changes AttachmentPickerAction from a sealed interface to a regular interface to enable custom implementations outside the SDK module. This allows developers to extend the attachment picker functionality with their own custom actions.

Key Changes

• Removed the sealed modifier from the AttachmentPickerAction interface
• Updated the changelog to document this breaking change

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
AttachmentPickerAction.kt	Removed sealed modifier to allow external implementations
CHANGELOG.md	Added changelog entry documenting the interface change

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[Copilot]

Pull Request Overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud