Warn on invalid noqa even when there are no diagnostics (#16178)
On `main` we warn the user if there is an invalid noqa comment[^1] and
at least one of the following holds:
- There is at least one diagnostic
- A lint rule related to `noqa`s is enabled (e.g. `RUF100`)
This is probably strange behavior from the point of view of the user, so
we now show invalid `noqa`s even when there are no diagnostics.
Closes #12831
[^1]: For the current definition of "invalid noqa comment", which may be
expanded in #12811 . This PR is independent of loc. cit. in the sense
that the CLI warnings should be consistent, regardless of which `noqa`
comments are considered invalid.
