cleanup: fix typings in wheels.py

[shubhbapna]

part of #226

fixes the following errors:

src/fromager/wheels.py:30: error: Call to untyped function "_createenv" in typed context  [no-untyped-call]
src/fromager/wheels.py:36: error: Function is missing a return type annotation  [no-untyped-def]
src/fromager/wheels.py:36: note: Use "-> None" if function does not return a value
src/fromager/wheels.py:42: error: List item 3 has incompatible type "Path"; expected "str"  [list-item]
src/fromager/wheels.py:54: error: Argument 1 to "run" has incompatible type "list[object]"; expected "list[str]"  [arg-type]
src/fromager/wheels.py:68: error: Argument "cwd" to "run" has incompatible type "Path"; expected "str | None"  [arg-type]
src/fromager/wheels.py:120: error: Missing type parameters for generic type "dict"  [type-arg]

[tiran]

Looks ok except for extra_environ argument.