pacman: Fail fast when 'rc != 0'
pacman: Fail fast when 'rc != 0'

We fail-fast and display 'stderr' in case 'pacman' returns with 'rc != 0'.
There is no point computing 'module._diff' in such case anyway.

Fixes #23910

(cherry picked from commit 8c6a2a848cf6a6d6522c8f5be56decf8df1ed6ab)

thaim/ansible,thaim/ansible