Fix three coverity issues

Reported here:
https://mail.kde.org/pipermail/konsole-devel/2022-July/041429.html

- Use delete[] to free array allocated with new.
- Don't separate two cases which are handled identically.
- In vt100 parsing state machine no need to handle in specific states
  characters which are handles identically in all states.

(cherry picked from commit 24b0c08d)