Werk #16633: Logfile pattern analyzer: Fix crash for first rule without regex pattern

The "Logfile pattern analyzer" page crashed when the first "Logfile pattern" rule in place did not hold a regex pattern and a later rule did hold a regex pattern. The rendering of the table of rules would crash with

Internal error: list index out of range

This is fixed and all rules are rendered as expected.

Zur Liste aller Werks