ScopeMetrics without InstrumentationScope causes NullReferenceException in dashboard

[WIStudent]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I am using the dashboard as a standalone docker container (Aspire version: 9.1.0+2a8f48ea5811f317a26405eb315aa315cc9e3cea) and trying to push some metrics using OTLP/HTTP to /v1/metrics. The metrics are generated and pushed by the micrometer-registry-otlp library, which does not add an InstrumentationScope to the ScopeMetrics. This should be valid according to OpenTelemetry's protobuf definition

message ScopeMetrics {
  // The instrumentation scope information for the metrics in this message.
  // Semantically when InstrumentationScope isn't set, it is equivalent with
  // an empty instrumentation scope name (unknown).
  opentelemetry.proto.common.v1.InstrumentationScope scope = 1;

but causes a NullReferenceException in the Aspire dashboard:

info: Aspire.Dashboard.Otlp.Storage.TelemetryRepository[0]
      Error adding metric instrument hibernate.cache.update.timestamps.requests.
      System.NullReferenceException: Object reference not set to an instance of an object.
        at Aspire.Dashboard.Otlp.Model.OtlpApplication.AddMetrics(AddContext context, RepeatedField`1 scopeMetrics) in /_/src/Aspire.Dashboard/Otlp/Model/OtlpApplication.cs:line 62

aspire/src/Aspire.Dashboard/Otlp/Model/OtlpApplication.cs

Line 62 in 2a8f48e

var instrumentKey = new OtlpInstrumentKey(sm.Scope.Name, metric.Name);

does not seem to consider the case where sm.Scope can be null.

Expected Behavior

Should parse the metric without throwing an exception.

Steps To Reproduce

See above

Exceptions (if any)

System.NullReferenceException

.NET Version info

No response

Anything else?

No response