Rename AggregatedMetricSample to AggregatedMetricValue

In out terminology, we refer to a "sample" as a data structure that stores
a value alongside a timestamp. Since the message `AggregatedMetricSample`
does not contain timestamps, it needs to be renamed.

Signed-off-by: Tiyash Basu <tiyash.basu@frequenz.com>

RELEASE_NOTES.md

@@ -33,6 +33,9 @@
 - Renamed `SimpleMetricSample` to `SimpleMetricValue`, because it does not
   contain a timestamp, so it does not represent a sample but a value.
 
+- Renamed `AggregatedMetricSample` to `AggregatedMetricValue`, because it does not
+  contain a timestamp, so it does not represent a sample but a value.
+
 ## New Features
 
 - Added a `Frequenz.api.common.v1.types.Decimal` type, compatible with

proto/frequenz/api/common/v1/metrics/metric_sample.proto

@@ -31,7 +31,7 @@ message SimpleMetricValue {
 // summaries—minimum, maximum, and average values. Individual measurements are
 // are optional, accommodating scenarios where only subsets of this information
 // are available.
-message AggregatedMetricSample {
+message AggregatedMetricValue {
   // The derived average value of the metric.
   float avg_value = 2;
 
@@ -46,19 +46,19 @@ message AggregatedMetricSample {
 }
 
 // MetricSampleVariant serves as a union type that can encapsulate either a
-// `SimpleMetricValue` or an `AggregatedMetricSample`.
+// `SimpleMetricValue` or an `AggregatedMetricValue`.
 //
 // This message is designed to offer flexibility in capturing different
 // granularities of metric samples—either a simple single-point measurement
 // or an aggregated set of measurements for a metric.
 //
 // A `MetricSampleVariant` can hold either a `SimpleMetricValue` or an
-// `AggregatedMetricSample`, but not both simultaneously. Setting one will
+// `AggregatedMetricValue`, but not both simultaneously. Setting one will
 // nullify the other.
 message MetricSampleVariant {
   oneof metric_sample_type {
     SimpleMetricValue simple_metric = 1;
-    AggregatedMetricSample aggregated_metric = 2;
+    AggregatedMetricValue aggregated_metric = 2;
   }
 }