Chore: Swap out use of backend plugin SDK's backend.Logger (#33783)

* Remove use of backend SDKs backend.Logger

* reorder imports

* FIx logger name

Co-authored-by: Marcus Efraimsson <marcus.efraimsson@gmail.com>

Co-authored-by: Marcus Efraimsson <marcus.efraimsson@gmail.com>

pkg/expr/nodes.go

@@ -10,10 +10,15 @@ import (
 	"github.com/grafana/grafana-plugin-sdk-go/data"
 	"github.com/grafana/grafana/pkg/expr/classic"
 	"github.com/grafana/grafana/pkg/expr/mathexp"
+	"github.com/grafana/grafana/pkg/infra/log"
 
 	"gonum.org/v1/gonum/graph/simple"
 )
 
+var (
+	logger = log.New("expr")
+)
+
 // baseNode includes commmon properties used across DPNodes.
 type baseNode struct {
 	id    int64
@@ -241,7 +246,7 @@ func (dn *DSNode) Execute(ctx context.Context, vars mathexp.Vars, s *Service) (m
 		if len(qr.Frames) == 1 {
 			frame := qr.Frames[0]
 			if frame.TimeSeriesSchema().Type == data.TimeSeriesTypeNot && isNumberTable(frame) {
-				backend.Logger.Debug("expression datasource query (numberSet)", "query", refID)
+				logger.Debug("expression datasource query (numberSet)", "query", refID)
 				numberSet, err := extractNumberSet(frame)
 				if err != nil {
 					return mathexp.Results{}, err
@@ -257,7 +262,7 @@ func (dn *DSNode) Execute(ctx context.Context, vars mathexp.Vars, s *Service) (m
 		}
 
 		for _, frame := range qr.Frames {
-			backend.Logger.Debug("expression datasource query (seriesSet)", "query", refID)
+			logger.Debug("expression datasource query (seriesSet)", "query", refID)
 			series, err := WideToMany(frame)
 			if err != nil {
 				return mathexp.Results{}, err