Allow user to select the SDK version from a drop-down box in the generate SDK step for data plane

**Scenario:** The release planner app always selects the most recent version for the SDK release. However, services can have multiple releases in progress. In this scenario, Ronnie was experimenting with using the release plan for the "SDK team releases the SDK on behalf of the service partner" use cases. There were already other releases in progress, so he needs to choose the version that relates to the SDKs that he is releasing not the "next" version.

**Requirement:** Show all versions and allow user to select the version.

**Link to Event Grid Namespace release plan** - https://aka.ms/sdk-release-planner?release-plan-id=16511fa0-f719-ef11-9f8a-0022480bd0ae