[allwpilib codex] Update GamepadChooserTest to camel_case

[pjreiniger]

Problem description

wpilibsuite/allwpilib#9041 (review)

With the wpilib bindings now generated as snake_case and enum values as CAPS_CASE, this example still calls setMode, Mode.Line, addOptions, and the other camelCase chooser/display methods in both autonomous constructors. Running the DSGamepadChooser example now raises AttributeError before the opmodes can be used; update these calls to the same names used by the converted tests (set_mode, Mode.LINE, add_options, etc.).

Operating System

Linux

Installed Python Packages

Reproducible example code

[virtuald]

I think this example hasn't been moved over to robotpy yet?