Fix CanHandleMissingProfilePaths test: use .ToString() on GetVariable result

Agent-Logs-Url: https://github.com/PowerShell/PowerShellEditorServices/sessions/6d4f3ac9-ed54-4532-97ae-33f69934f59a

Co-authored-by: JustinGrote <15258962+JustinGrote@users.noreply.github.com>

Author: Copilot

test/PowerShellEditorServices.Test/Session/PsesInternalHostTests.cs

@@ -119,7 +119,7 @@ await psesHost.ExecuteDelegateAsync(
                     pwsh.SetProfileVariable(emptyProfilePaths);
                     pwsh.LoadProfileScripts(emptyProfilePaths);
 
-                    Assert.Equal(emptyProfilePaths.CurrentUserCurrentHost, pwsh.Runspace.SessionStateProxy.GetVariable("PROFILE"));
+                    Assert.Equal(emptyProfilePaths.CurrentUserCurrentHost, pwsh.Runspace.SessionStateProxy.GetVariable("PROFILE")?.ToString());
                     Assert.Empty(pwsh.Commands.Commands);
                 },
                 CancellationToken.None);