Optimize queries for (non-)empty labels (#9966)

Signed-off-by: Arve Knudsen <arve.knudsen@gmail.com>

Author: aknuds1

go.mod

@@ -284,7 +284,7 @@ require (
 )
 
 // Using a fork of Prometheus with Mimir-specific changes.
-replace github.com/prometheus/prometheus => github.com/grafana/mimir-prometheus v0.0.0-20241112081901-33bfe839e4ef
+replace github.com/prometheus/prometheus => github.com/grafana/mimir-prometheus v0.0.0-20241120160701-db938c3ceac8
 
 // Replace memberlist with our fork which includes some fixes that haven't been
 // merged upstream yet:

go.sum

@@ -1276,8 +1276,8 @@ github.com/grafana/gomemcache v0.0.0-20241016125027-0a5bcc5aef40 h1:1TeKhyS+pvzO
 github.com/grafana/gomemcache v0.0.0-20241016125027-0a5bcc5aef40/go.mod h1:IGRj8oOoxwJbHBYl1+OhS9UjQR0dv6SQOep7HqmtyFU=
 github.com/grafana/memberlist v0.3.1-0.20220714140823-09ffed8adbbe h1:yIXAAbLswn7VNWBIvM71O2QsgfgW9fRXZNR0DXe6pDU=
 github.com/grafana/memberlist v0.3.1-0.20220714140823-09ffed8adbbe/go.mod h1:MS2lj3INKhZjWNqd3N0m3J+Jxf3DAOnAH9VT3Sh9MUE=
-github.com/grafana/mimir-prometheus v0.0.0-20241112081901-33bfe839e4ef h1:DH1rR0nzlOIPXvLDQjmlyEtr4g+rqrN/iklns+m3w0U=
-github.com/grafana/mimir-prometheus v0.0.0-20241112081901-33bfe839e4ef/go.mod h1:M4xmfU7SsnzjkLwJfvNen/MxAZp4DJPfipLzeib+0gQ=
+github.com/grafana/mimir-prometheus v0.0.0-20241120160701-db938c3ceac8 h1:y9kz0U/FgKalDnzS+2TbTdKytdvZrzqqX4eh3I26vZA=
+github.com/grafana/mimir-prometheus v0.0.0-20241120160701-db938c3ceac8/go.mod h1:M4xmfU7SsnzjkLwJfvNen/MxAZp4DJPfipLzeib+0gQ=
 github.com/grafana/opentracing-contrib-go-stdlib v0.0.0-20230509071955-f410e79da956 h1:em1oddjXL8c1tL0iFdtVtPloq2hRPen2MJQKoAWpxu0=
 github.com/grafana/opentracing-contrib-go-stdlib v0.0.0-20230509071955-f410e79da956/go.mod h1:qtI1ogk+2JhVPIXVc6q+NHziSmy2W5GbdQZFUHADCBU=
 github.com/grafana/prometheus-alertmanager v0.25.1-0.20240930132144-b5e64e81e8d3 h1:6D2gGAwyQBElSrp3E+9lSr7k8gLuP3Aiy20rweLWeBw=