Enable Multi-Vote Support in Polls Extension (SDK & UI Kit)

Description:

The current Polls Extension allows each user (UID) to submit only one vote per poll, and the SDK enforces a single-response model. A client has requested support for multiple selections within the same poll, allowing a user to vote for more than one option.

To address this requirement, we need updates across both the SDK and the UI Kit:

• Add multi-vote capability at the Polls Extension level.

• Update SDK methods to accept and process multiple responses from the same UID.

• Update UI Kit components to allow users to select multiple options and submit them in a single action.

• Ensure backward compatibility for apps that rely on the existing single-vote behavior.

This enhancement will enable richer polling experiences and align with modern multi-choice survey requirements.