Filter irrelevant requirements from source annotations (#3479)
## Summary
If a requirement is omitted due to a marker expression, we shouldn't
include it as the "source" of a package in the output.
For example, if your constraints include `pathspec ; python_version <
'3.12'`, and you're on Python 3.12, we should _not_ include the
constraint file as a "source" in the output annotations.
