Vast.ai - Instance Label Selection

Description

Due to a frontend issue on vast.ai, the label located at the very right of the Instances page cannot be clicked. This adds a "Select Label" button to the left of the "All" tab in the Instances page for easy label selection via radio button dialog. The button is styled to match the tab appearance and is fully visible. The radio button dialog only shows actual label names (filters out non-label items). Only one label can be selected at a time.