Fix .NET session lifecycle replay mismatch in PR 1728

Restore the second lifecycle prompt to 'Say world' to match the existing session_lifecycle snapshot and avoid replay cache misses in CI.

Related to issue #1682 but does not fix #1682.

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

Author: edburns

dotnet/test/E2E/SessionLifecycleE2ETests.cs

@@ -25,7 +25,7 @@ public async Task Should_List_Created_Sessions_After_Sending_A_Message()
 
         // Sessions must have activity to be persisted to disk
         await session1.SendAndWaitAsync(new MessageOptions { Prompt = "Say hello" });
-        await session2.SendAndWaitAsync(new MessageOptions { Prompt = "Say hi" });
+        await session2.SendAndWaitAsync(new MessageOptions { Prompt = "Say world" });
 
         IList<SessionMetadata>? sessions = null;
         await TestHelper.WaitForConditionAsync(