Remove SensorMetricSample in favour of MetricSample

This commit removes the `SensorMetricSample` message in favour of using
`MetricSample` for sensors. The `SensorMetricSample` message was
a subset of the `MetricSample` message.

From a design perspective focused on consistency, flexibility, and
minimizing API surface area while handling variations via optional
fields (which is idiomatic in Protobuf3), there's a strong argument that
`SensorMetricSample` is redundant and potentially confusing, and that
having only `MetricSample` is a cleaner design.

Signed-off-by: Tiyash Basu <[email protected]>

Author: tiyash-basu-frequenz

RELEASE_NOTES.md

@@ -25,6 +25,7 @@
 - Renamed `ComponentCatgoryMetadataVariant` to `ElectricalComponentCategorySpecificInfo`.
 - Renamed field `ElectricalComponent.category_type` to `ElectricalComponent.category_specific_info` to better reflect its purpose.
 - Renamed `metric_sample.proto` to `metrics.proto` to better reflect its content.
+- Remove `SensorMetricSample` in favour of using `MetricSample` for sensors.
 
 ## Bug Fixes
 

proto/frequenz/api/common/v1/microgrid/sensors/sensors.proto

@@ -166,7 +166,7 @@ message SensorDiagnostic {
   // Optional human-readable message providing additional context.
   string message = 3;
 }
-
+bopids
 // Representation of a sensor state and errors.
 message SensorState {
   // The time at which the state was sampled.
@@ -207,18 +207,6 @@ message SensorState {
   repeated SensorDiagnostic errors = 4;
 }
 
-// Representation of a sampled sensor metric along with its value.
-message SensorMetricSample {
-  // The UTC timestamp of when the metric was sampled.
-  google.protobuf.Timestamp sampled_at = 1;
-
-  // The metric that was sampled.
-  frequenz.api.common.v1.metrics.Metric metric = 2;
-
-  // The value of the sampled metric.
-  frequenz.api.common.v1.metrics.MetricValueVariant value = 3;
-}
-
 // SensorData message aggregates multiple metrics, operational states, and
 // errors, related to a specific microgrid sensor.
 //
@@ -233,11 +221,15 @@ message SensorMetricSample {
 //          sampled_at: "2023-10-01T00:00:00Z",
 //          metric: "METRIC_SENSOR_TEMPERATURE",
 //          value: metric_value_variant: {simple_metric: {value: 23.5},
+//          bounds: {}
+//          source: {}
 //        },
 //        {
 //          sampled_at: "2023-10-01T00:00:00Z",
 //          metric: "METRIC_SENSOR_RELATIVE_HUMIDITY",
 //          value: metric_value_variant: {simple_metric: {value: 23.5},
+//          bounds: {}
+//          source: "humidity_sensor_1"
 //        }
 //      ],
 //      states: [
@@ -254,7 +246,7 @@ message SensorData {
   uint64 sensor_id = 1;
 
   // List of measurements for a metric of the specific microgrid sensor.
-  repeated SensorMetricSample metric_samples = 2;
+  repeated frequenz.api.common.v1.metrics.MetricSample metric_samples = 2;
 
   // List of states of a specific microgrid sensor.
   repeated SensorState states = 3;