[DiagnosticsClient] Keep UserEvents Probe API internal

Support to probe any CommandSet/CommandID support may be added in the
future, so to avoid conflicting APIs, keep this internal for now as the
query is only relevant to dotnet-trace collect-linux.

Author: mdh1418

src/Microsoft.Diagnostics.NETCore.Client/DiagnosticsClient/DiagnosticsClient.cs

@@ -156,29 +156,14 @@ public Task<EventPipeSession> StartEventPipeSessionAsync(EventPipeSessionConfigu
         /// <returns>
         /// A boolean indicating whether the runtime understands the CollectTracing5 user_events IPC command.
         /// </returns>
-        public bool SupportsEventPipeUserEventsCommand()
+        internal bool SupportsEventPipeUserEventsCommand()
         {
             IpcMessage probe = CreateUserEventsCapabilityProbeMessage();
             IpcMessage response = IpcClient.SendMessage(_endpoint, probe);
 
             return IsCommandSupportedFromResponse(response);
         }
 
-        /// <summary>
-        /// Check whether the target runtime understands the CollectTracing5 user_events IPC command.
-        /// </summary>
-        /// <param name="token">The token to monitor for cancellation requests.</param>
-        /// <returns>
-        /// A task that completes with a boolean indicating whether the runtime understands the CollectTracing5 user_events IPC command.
-        /// </returns>
-        public async Task<bool> SupportsEventPipeUserEventsCommandAsync(CancellationToken token = default)
-        {
-            IpcMessage probe = CreateUserEventsCapabilityProbeMessage();
-            IpcMessage response = await IpcClient.SendMessageAsync(_endpoint, probe, token).ConfigureAwait(false);
-
-            return IsCommandSupportedFromResponse(response);
-        }
-
         /// <summary>
         /// Trigger a core dump generation.
         /// </summary>