Fix IDAKLU output_variables to work with extrapolation events #10636

Job	Run time
style	35s
Example notebooks (ubuntu-latest / Python 3.12)	18m 37s
Doctests (ubuntu-latest / Python 3.11)	3m 32s
Tests (ubuntu-latest / Python 3.9)	29m 36s
Example scripts (ubuntu-latest / Python 3.12)	14m 10s
Tests (ubuntu-latest / Python 3.10)	30m 31s
Tests (ubuntu-latest / Python 3.11)	27m 6s
Tests (ubuntu-latest / Python 3.12)	34m 55s
Tests (macos-12 / Python 3.9)	40m 11s
Tests (macos-12 / Python 3.10)	24m 57s
Tests (macos-12 / Python 3.11)	26m 40s
Tests (macos-12 / Python 3.12)	26m 26s
Tests (macos-14 / Python 3.9)	13m 48s
Tests (macos-14 / Python 3.10)	15m 46s
Tests (macos-14 / Python 3.11)	15m 33s
Tests (macos-14 / Python 3.12)	9m 25s
Tests (windows-latest / Python 3.9)	31m 14s
Tests (windows-latest / Python 3.10)	32m 16s
Tests (windows-latest / Python 3.11)	30m 30s
Tests (windows-latest / Python 3.12)	26m 6s
	7h 31m 54s

Provide feedback