[cmd/mdatagen] Fix Histogram metric generation logic & reduce zapgrpc noise

cmd/mdatagen/internal/samplescraper/documentation.md

@@ -70,6 +70,16 @@ The metric will be become optional soon.
 | ---- | ----------- | ---------- | ----------------------- | --------- | --------- | ------------------- |
 | s | Sum | Int | Cumulative | true | Beta | [system.cpu.time](https://github.com/open-telemetry/semantic-conventions/blob/v1.38.0/docs/system/system-metrics.md#metric-systemcputime) |
 
+### system.cpu.utilization
+
+Gauge double metric enabled by default.
+
+The metric will be become optional soon.
+
+| Unit | Metric Type | Value Type | Aggregation Temporality | Stability |
+| ---- | ----------- | ---------- | ----------------------- | --------- |
+| 1 | Histogram | Double | Unspecified | Beta |
+
 ## Optional Metrics
 
 The following metrics are not emitted by default. Each of them can be enabled by applying the following configuration:

cmd/mdatagen/internal/samplescraper/internal/metadata/testdata/config.yaml

@@ -13,6 +13,8 @@ all_set:
       enabled: true
     system.cpu.time:
       enabled: true
+    system.cpu.utilization:
+      enabled: true
   resource_attributes:
     map.resource.attr:
       enabled: true
@@ -44,6 +46,8 @@ none_set:
       enabled: false
     system.cpu.time:
       enabled: false
+    system.cpu.utilization:
+      enabled: false
   resource_attributes:
     map.resource.attr:
       enabled: false

cmd/mdatagen/internal/samplescraper/metadata.yaml

@@ -181,3 +181,14 @@ metrics:
       aggregation_temporality: cumulative
     semantic_convention:
       ref: https://github.com/open-telemetry/semantic-conventions/blob/v1.38.0/docs/system/system-metrics.md#metric-systemcputime
+
+  system.cpu.utilization:
+    enabled: true
+    stability:
+      level: beta
+    description: Gauge double metric enabled by default.
+    extended_documentation: The metric will be become optional soon.
+    unit: "1"
+    histogram:
+      value_type: double
+      bucket_boundaries: [0.0, 0.25, 0.5, 0.75, 1.0]