Default option for close/reopen PR/issue should be "no" (safer)

[wleoncio]

Is your feature request related to a problem? Please describe.
It feels unsafe to have the default be "Y", especially in situations where x/X is pressed accidentally (e.g., when the user was expecting to be operating on a different window, see issue #595).

Describe the solution you'd like
The default option for closing/reopening should be "N". This also makes gh-dash more compliant to popular good practices like human error prevention, conservative/defensive design, and even the Principle of Least Astonishment (POLA).

Describe alternatives you've considered
None

Additional context
None