Make agent reload test runtime-compatible

Use a unique reload agent name and assert reload results match the subsequent list result instead of depending on whether the runtime preserves session-configured agents after reload.

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

Author: stephentoub

dotnet/test/E2E/RpcAgentE2ETests.cs

@@ -2,6 +2,7 @@
  *  Copyright (c) Microsoft Corporation. All rights reserved.
  *--------------------------------------------------------------------------------------------*/
 
+using GitHub.Copilot.SDK.Rpc;
 using GitHub.Copilot.SDK.Test.Harness;
 using Xunit;
 using Xunit.Abstractions;
@@ -104,10 +105,11 @@ public async Task Should_Return_Empty_List_When_No_Custom_Agents_Configured()
     [Fact]
     public async Task Should_Call_Agent_Reload()
     {
-        var session = await CreateSessionAsync(new SessionConfig { CustomAgents = [CreateReloadAgent()] });
+        var reloadAgent = CreateReloadAgent($"reload-test-agent-{Guid.NewGuid():N}");
+        var session = await CreateSessionAsync(new SessionConfig { CustomAgents = [reloadAgent] });
 
         var before = await session.Rpc.Agent.ListAsync();
-        Assert.Single(before.Agents, agent => string.Equals(agent.Name, "reload-test-agent", StringComparison.Ordinal));
+        AssertReloadAgent(before.Agents, reloadAgent);
 
         var result = await session.Rpc.Agent.ReloadAsync();
         var current = await session.Rpc.Agent.ListAsync();
@@ -120,6 +122,13 @@ public async Task Should_Call_Agent_Reload()
             current.Agents.Select(agent => agent.DisplayName).OrderBy(name => name, StringComparer.Ordinal));
     }
 
+    private static void AssertReloadAgent(IEnumerable<AgentInfo> agents, CustomAgentConfig expected)
+    {
+        var agent = Assert.Single(agents, agent => string.Equals(agent.Name, expected.Name, StringComparison.Ordinal));
+        Assert.Equal(expected.DisplayName, agent.DisplayName);
+        Assert.Equal(expected.Description, agent.Description);
+    }
+
     private static List<CustomAgentConfig> CreateCustomAgents() =>
     [
         new()
@@ -138,10 +147,10 @@ private static List<CustomAgentConfig> CreateCustomAgents() =>
         }
     ];
 
-    private static CustomAgentConfig CreateReloadAgent() =>
+    private static CustomAgentConfig CreateReloadAgent(string name) =>
         new()
         {
-            Name = "reload-test-agent",
+            Name = name,
             DisplayName = "Reload Test Agent",
             Description = "Used by the agent reload RPC test.",
             Prompt = "You are a reload test agent.",