Register featuregate, otherwise does not work (open-telemetry#16269)

Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>

Signed-off-by: Bogdan Drutu <bogdandrutu@gmail.com>

.chloggen/fixunregistergate.yaml

@@ -0,0 +1,11 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: bug_fix
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: spanmetricsprocessor
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Register `processor.spanmetrics.PermissiveLabelSanitization` featuregate, which was only defined but not registered.
+
+# One or more tracking issues related to the change
+issues: [16269]

processor/spanmetricsprocessor/config.go

@@ -23,10 +23,19 @@ import (
 )
 
 const (
-	delta      = "AGGREGATION_TEMPORALITY_DELTA"
-	cumulative = "AGGREGATION_TEMPORALITY_CUMULATIVE"
+	delta                  = "AGGREGATION_TEMPORALITY_DELTA"
+	cumulative             = "AGGREGATION_TEMPORALITY_CUMULATIVE"
+	dropSanitizationGateID = "processor.spanmetrics.PermissiveLabelSanitization"
 )
 
+func init() {
+	featuregate.GetRegistry().MustRegisterID(
+		dropSanitizationGateID,
+		featuregate.StageAlpha,
+		featuregate.WithRegisterDescription("Controls whether to change labels starting with '_' to 'key_'"),
+	)
+}
+
 // Dimension defines the dimension name and optional default value if the Dimension is missing from a span attribute.
 type Dimension struct {
 	Name    string  `mapstructure:"name"`
@@ -64,12 +73,6 @@ type Config struct {
 	skipSanitizeLabel bool
 }
 
-var dropSanitizationGate = featuregate.Gate{
-	ID:          "processor.spanmetrics.PermissiveLabelSanitization",
-	Enabled:     false,
-	Description: "Controls whether to change labels starting with '_' to 'key_'",
-}
-
 // GetAggregationTemporality converts the string value given in the config into a AggregationTemporality.
 // Returns cumulative, unless delta is correctly specified.
 func (c Config) GetAggregationTemporality() pmetric.AggregationTemporality {

processor/spanmetricsprocessor/factory.go

@@ -44,7 +44,7 @@ func createDefaultConfig() component.ProcessorConfig {
 		ProcessorSettings:      config.NewProcessorSettings(component.NewID(typeStr)),
 		AggregationTemporality: "AGGREGATION_TEMPORALITY_CUMULATIVE",
 		DimensionsCacheSize:    defaultDimensionsCacheSize,
-		skipSanitizeLabel:      featuregate.GetRegistry().IsEnabled(dropSanitizationGate.GetID()),
+		skipSanitizeLabel:      featuregate.GetRegistry().IsEnabled(dropSanitizationGateID),
 	}
 }