Delete ASP.NET Core metrics entry (#45874)

Author: gewarren

docs/breadcrumb/toc.yml

@@ -31,9 +31,6 @@ items:
           - name: Orleans
             tocHref: /dotnet/orleans/
             topicHref: /dotnet/orleans/index
-          - name: ASP.NET Core metrics
-            tocHref: /aspnet/core/log-mon/metrics/built-in
-            topicHref: /aspnet/core/log-mon/metrics/built-in
           - name: .NET Framework
             tocHref: /dotnet/framework/
             topicHref: /dotnet/framework/index