ENH: Drop player strategies in graphical interface

[AbhijeetKrishnan]

Version: Gambit v16.0.2
Type: GUI
Platform: Windows 11

I'm analyzing a simple 2-player zero-sum game by entering payoff values in the strategic table view. While there is a clear way to add a player strategy by clicking on the table icon next to the player name, there doesn't seem to be an obvious way to delete a player strategy. This would be useful for me to explore variations of the game with different player strategies easily.

[AbhijeetKrishnan]

@tturocy @skunath @andrioni @dkasak Could we have some resolution for this?