We want to avoid terminating the whole loop here, because it will cause
parameters that should be removed to not be removed, since we are
terminating early. In this specific case, `param2` is processed before
`param1` due to the reversing of `route.parts`, and since `param2` fails
the check on this line, it would previously cause the whole loop to
fail, and `param1` would still be in `parameterized_parts`. Now, we are
simply calling `next`, which is the intended behavior.

Introduced by 8ca8a2d7.

Fixes #27454.