Simplify lambda to method group in OtlpResource.AddMetrics (#18355)

The lambda 'm => GetMetricDataPointCount(m)' can be reduced to the
method group 'GetMetricDataPointCount'. The IDE0200 analyzer ('Lambda
expression can be removed') fires nondeterministically in command-line
builds and was breaking local builds with -warnaserror. Reducing it to
a method group removes the latent build break. No behavior change.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: sebastienros

src/Aspire.Dashboard/Otlp/Model/OtlpResource.cs

@@ -70,7 +70,7 @@ public void AddMetrics(AddContext context, RepeatedField<ScopeMetrics> scopeMetr
             {
                 if (!OtlpHelpers.TryGetOrAddScope(_meters, sm.Scope, Context, TelemetryType.Metrics, out var scope))
                 {
-                    context.FailureCount += sm.Metrics.Sum(m => GetMetricDataPointCount(m));
+                    context.FailureCount += sm.Metrics.Sum(GetMetricDataPointCount);
                     continue;
                 }