Comment update: clarify we need sdk in install-dotnet.yml due to …

…`asp.net core` runtime (#5428)

eng/pipelines/templates/steps/install-dotnet.yml

@@ -16,12 +16,17 @@ steps:
     retryCountOnTaskFailure: 3
     inputs:
       # We must install sdk, not just runtime, as it is required by some of our tools, like test-proxy.
-      # For additional context, see PR: https://github.com/Azure/azure-sdk-tools/pull/5405
+      # Specifically, test-proxy requires asp.net core runtime, which is installed only when sdk option
+      # is selected, per: https://github.com/microsoft/azure-pipelines-tasks/issues/14405
+      #
+      # For additional context, see:
+      # https://github.com/Azure/azure-sdk-tools/pull/5405#discussion_r1105006774
+      # https://github.com/Azure/azure-sdk-tools/pull/5405
       packageType: sdk
       version: 6.0.x
       # performMultiLevelLookup comes into play when given .NET executable target runtime is different
       # than the installed .NET SDK. Without this, such runtime would not be found.
       performMultiLevelLookup: true
 
 # Future work: add NuGet packages caching. See:
-# https://github.com/Azure/azure-sdk-tools/issues/5086  
+# https://github.com/Azure/azure-sdk-tools/issues/5086