fix: enable display and switch of firing mode for shape targetmode

[ekaratzas]

Purpose of change

This PR addresses the issue of not being able to switch firing mode when using birdshot with double barreled shotgun.
With this change, when in TargetMode::Shape and actually using a gun, the firing UI will:

• show the current firing mode
• provide hotkey for switching firing modes

Fixes #4071

Describe the solution

Players can now switch firing modes from the shooting/firing menu when using a gun that fires in a 'shape' / area of effect.

Describe alternatives you've considered

Testing

Made character with double barreled shotgun. Tries this change with both birdshot and buckshot to see that double firing mode can be changed in the shooting ui and that it actually shoots both barrels. Buckshot shooting seems to work the same.

Additional context

Checklist

[scarf005]

hi, it'd be appreciated to not mention issues by their hash (#123) in PR title, as the links do not work in regular git commits.

also, please check https://docs.cataclysmbn.org/en/contribute/changelog_guidelines/ for PR title guideline.

[ekaratzas]

hi, it'd be appreciated to not mention issues by their hash (#123) in PR title, as the links do not work in regular git commits.

also, please check https://docs.cataclysmbn.org/en/contribute/changelog_guidelines/ for PR title guideline.

thanks @scarf005 let me know if the latest PR title looks ok.

[scarf005]