Close terminal after external call and cmd execution

## Problem
I don't wanna install xterm to run scripts with .desktop (`Terminal=true`). In order to fix that, I'm using `io.elementary.terminal -x run_script.sh`. The problem is that, after execution, the terminal doesn't close. I've tried many workarounds using `exit` without luck. It only worked using:
```
Exec=io.elementary.terminal -e bash run_script.sh;exit
```
With gnome-terminal and xterm, it exists after cmd execution.

## Proposal
Close terminal after cmd execution.