Bug: display_appropriate_suits_list crashes on empty suits list

### Summary
display_appropriate_suits_list/2 crashes when suits is empty.

### Location
copi.owasp.org/lib/copi_web/live/game_live/game_form_helpers.ex

### Repro
Call display_appropriate_suits_list(webapp, []).

### Actual
hd(suits) raises on empty list and crashes the LiveView process.

### Expected
Handle empty list safely and return generated suits for the selected edition.