fastkml

00f4b985 - Fix zuban type errors: one real bug and false-positive suppressions

Fix zuban type errors: one real bug and false-positive suppressions datetime_subelement_list_kwarg crashed on empty/missing subelement text instead of handling it gracefully, unlike its non-list sibling datetime_subelement_kwarg which already guards for this. Suppress the remaining checker false positives, each verified in isolation: lxml-stubs' nsmap typing doesn't model a None key (kml.py), the same truthy-narrowing idiom pygeoif itself uses internally for Point.coords (gx/track.py), a generic type[Enum] call misfiring mypy's Enum functional-API check (helpers.py), literal tuple widening in a Collection[Literal[...]] argument (strategies.py), and find()/find_all()'s recursive self-calls not being resolvable against their own overloads (utils.py).