Revert "Move self.therms_with_offset_func init" #5305

Job	Run time
Prepare	1m 0s
Shellcheck	4s
Dependency	6s
Ruff check and force	19s
Check commit	42s
Create pytest cache for Python 3.13.0	14s
Create pytest cache for Python 3.12	9s
Run pytest using Python 3.13.0	21s
Run pytest using Python 3.12	12s
Process test coverage	23s
Run mypy	23s
Build and publish Python 🐍 distributions 📦 to TestPyPI	27s
Process test complexity	13s
	4m 33s

Provide feedback