Handle the promise rejection if an interrupt occurs in the regular workflow of cli-executor

[jamesgeorge007]

Describe the bug

The cli-executor makes sure that the users aren't left out if they pass in an unknown flag. And if the user interrupts the regular workflow, a promise rejection occurs which is left unhandled.

What is the current behavior?

[webpack-cli] Promise rejection: is logged on to the console.

To Reproduce
Steps to reproduce the behavior:

Type in webpack-cli --unknown

ctrl/cmd+c would result in a promise rejection text being logged to the console.

Expected behavior

Handle the promise rejection thereby replacing what is currently logged with an appropriate message.

Screenshots

Additional context

N/A