`t:`, `:`, and `run` functions still utilizing gnome-terminal, not cosmic-term

[XV-02]

In the current launcher used in Gnome with Pop/Cosmic extensions, a user can execute a cli command using :, t:, and run which is leveraging gnome-terminal.

The cosmic-launcher is also currently still leveraging gnome-terminal instead of cosmic-term.

At a certain level, this may provide a bit of a safety net at current. I've found it useful for launching gnome-terminal itself on an nvidia system in light of the current incompatability between wgpu driven rendering for cosmic-term and proprietary nvidia drivers.

However, this is probably one of many changes that will need to be eventually made to cosmic-launcher's integrated features.