* Add new test cases for multiple name matchers in PromQL info function
* Fix handling of multiple name matchers in PromQL info function
---------
Signed-off-by: Jeanette Tan <jeanette.tan@grafana.com>
When filtering by a label that exists on both the input metric and
target_info (e.g., info(metric, {host_name="orbstack"}) where host_name
exists on both), the function incorrectly returned empty results.
The bug was in combineWithInfoVector: when no new labels were added
(because they all overlapped with base metric labels), the code entered
the "no match" filtering block even though an info series WAS matched.
The fix checks len(seenInfoMetrics) == 0 to correctly identify when no
info series matched. If an info series matched (seenInfoMetrics is
non-empty), the series is kept even if no new labels were added.
Fixes#17813
Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>
