Fix BPX bug when activation energies not provided #11125

Job	Run time
Example scripts (ubuntu-latest / Python 3.12)	13m 50s
Example notebooks (ubuntu-latest / Python 3.12)	19m 40s
Tests (ubuntu-latest / Python 3.9)	31m 20s
Tests (ubuntu-latest / Python 3.10)	30m 50s
Doctests (ubuntu-latest / Python 3.11)	3m 36s
style	25s
Tests (ubuntu-latest / Python 3.11)	27m 57s
Tests (ubuntu-latest / Python 3.12)	34m 32s
Tests (macos-13 / Python 3.9)	30m 55s
Tests (macos-13 / Python 3.10)	27m 12s
Tests (macos-13 / Python 3.11)	29m 6s
Tests (macos-13 / Python 3.12)	27m 3s
Tests (macos-14 / Python 3.9)	11m 28s
Tests (macos-14 / Python 3.10)	13m 24s
Tests (macos-14 / Python 3.11)	12m 26s
Tests (macos-14 / Python 3.12)	11m 47s
Tests (windows-latest / Python 3.9)	30m 28s
Tests (windows-latest / Python 3.10)	32m 38s
Tests (windows-latest / Python 3.11)	30m 27s
Tests (windows-latest / Python 3.12)	27m 20s
	7h 26m 24s

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