test(selftest): register WizardStateSmokeStep for v1.5.2 wizard flow

Variant 1 walks the FirstRunWizard state machine through Step 1 →
4 and commits with no pending values to verify the no-op
write-back path. Variant 2 picks Roleplay on Step 2, skips Step 3,
commits, and asserts LoadPreviousSession /
FilterIncludePreviousSessions stayed on their pre-test value —
pinning the null-semantics from Spec Z.176. ApplyRoleplay would
overwrite six privacy / retention fields, so the step snapshots
them before Variant 2 and CleanUp() restores them, keeping the
self-test idempotent across /xlperf runs. Catches state-machine
throws and CommitPending NREs that would otherwise surface as a
hard plugin crash during Finish ✓ clicks. Runs alongside the
existing three FontManager / ThemeSwitch self-test steps.

HellionChat/Plugin.cs

@@ -321,6 +321,7 @@ public sealed class Plugin : IAsyncDalamudPlugin
                 new SelfTests.ThemeSwitchSelfTestStep(this),
                 new SelfTests.FontManagerCtorSmokeStep(this),
                 new SelfTests.FontPushSmokeStep(this),
+                new SelfTests.WizardStateSmokeStep(this),
             ]);
 
             if (!Config.FirstRunCompleted)