Describe the bug

This works

{service_name="nginx-json"} | json user_identifier="[\"user-identifier\"]"

But this doesn't:

{service_name="nginx-json"} | json user_identifier="user-identifier"

But any other JSON prop (not containing a dash in the label name) doesn't need the bracket syntax

To Reproduce
Visit the links above.

Expected behavior
Shouldn't need to treat JSON parser prop values any differently just because they have a dash in the label name.