Support custom terminals for PowerToys Run Shell plugin

[michaelmdresser]

Description of the new feature / enhancement

I would like to customize the Shell plugin to use a shell other than cmd.exe, PowerShell.exe, or wt.exe.

Scenario when this would be used?

I have been using wezterm (https://wezfurlong.org/wezterm/index.html) and would like to have PowerToys Run launch that for the Shell plugin.

Supporting information

I see the settings file at %localappdata%\Microsoft\PowerToys\PowerToys Run\Settings\Plugins\Microsoft.Plugin.Shell\ShellPluginSettings.json (thanks to #3440 (comment)) but it appears that the Shell option is hardcoded based on an enum (I gather that from the description of #25661). I'd like to be able to set the Shell to a string or similar to launch a shell/terminal of my choice, e.g. wezterm.exe.

Other related issues/PRs that I found in case the context is helpful:

• [Run] Add options to run commands from different shells (in Settings or at runtime) #4283
• [PowerToys Run] Command Shell Options #9627
• Pt run - Shell selection #28121

[htcfreek]

We should wait until microsoft/terminal#16060 is implemented.