check for invalid header entity

[Ghesselink]

Header entity can only be FILE_DESCRIPTION, FILE_NAME or FILE_SCHEMA. Encountered a file with FILE_INFO, which doesn't give a fail somewhere else.
e.g. ifcopenshell.validate

 python3 -m ifcopenshell.validate fail_invalid_header_entity.ifc
Validating /home/geert/Documents/gherkin/packages/simple_spf/fork/step-file-parser/fixtures/fail_invalid_header_entity.ifc
No validation issues found.

After these changes

python3 -m ifcopenshell.simple_spf /home/geert/Documents/gherkin/packages/simple_spf/fork/step-file-parser/fixtures/fail_invalid_header_entity.ifc
On line 6 column 1:
Unexpected __anon_3 ('FILE_INFO')
Expecting ENDSEC
00006 | FILE_INFO(
        ^

For the validation service, this will cause the file to fail before reaching the header validation.

[aothms]

We do have something in ifcopenshell, but indeed if there is a header entity following the three specified ones it doesn't raise an error. Also, this is probably a better place to do that check. https://github.com/IfcOpenShell/IfcOpenShell/blob/d401e4c948482c02d789a890f897b6929928f504/src/ifcparse/IfcSpfHeader.cpp#L94-L110