Make the keypad "5" key send "\E[E" when NumLock is off

Summary:
When NumLock is off the keypad "5" key should send '\E[E' sequence; this
matches xterm behaviour.

BUG: 189116

Reviewers: #konsole, hindenburg

Reviewed By: #konsole, hindenburg

Subscribers: hindenburg, #konsole

Tags: #konsole

Differential Revision: https://phabricator.kde.org/D11958

(cherry picked from commit 2037c36a)