build: import GetPersistentVolumeClass from component-helpers

Signed-off-by: Yonatan Kahana <yonatankahana.il@gmail.com>

vendor/github.com/prometheus/common/expfmt/text_parse.go

@@ -299,17 +299,6 @@ func (p *TextParser) startLabelName() stateFn {
 		p.parseError(fmt.Sprintf("expected '=' after label name, found %q", p.currentByte))
 		return nil
 	}
-	// Check for duplicate label names.
-	labels := make(map[string]struct{})
-	for _, l := range p.currentMetric.Label {
-		lName := l.GetName()
-		if _, exists := labels[lName]; !exists {
-			labels[lName] = struct{}{}
-		} else {
-			p.parseError(fmt.Sprintf("duplicate label names for metric %q", p.currentMF.GetName()))
-			return nil
-		}
-	}
 	return p.startLabelValue
 }