Remove CredentialsChangedNotifier event bus, superseded by the detector

#22926's first-login hardening signalled credential establishment through a
process-global CredentialsChangedNotifier that the banner collected against a
re-read of getSelectedSite() — the staleness race called out in #22942.
EditorCapabilityDetector.refresh(storedSite), called from the mint path on the
exact mutated SiteModel, replaces that coordination, so drop the notifier and
its wiring in ApplicationPasswordLoginHelper.

Author: jkmassel

WordPress/src/main/java/org/wordpress/android/ui/accounts/login/ApplicationPasswordLoginHelper.kt

@@ -46,7 +46,6 @@ class ApplicationPasswordLoginHelper @Inject constructor(
     private val discoverSuccessWrapper: DiscoverSuccessWrapper,
     private val crashLogging: CrashLogging,
     private val wpApiClientProvider: WpApiClientProvider,
-    private val credentialsChangedNotifier: CredentialsChangedNotifier,
 ) {
     private var processedAppPasswordData: String? = null
 
@@ -149,7 +148,6 @@ class ApplicationPasswordLoginHelper @Inject constructor(
                 }
                 wpApiClientProvider.clearSelfHostedClient(site.id)
                 dispatcherWrapper.updateApplicationPassword(site)
-                credentialsChangedNotifier.notifyChanged(site.id)
                 trackSuccessful(effectiveUrlLogin.siteUrl)
                 trackCreated(creationSource, success = true)
                 processedAppPasswordData = effectiveUrlLogin.siteUrl

WordPress/src/main/java/org/wordpress/android/ui/accounts/login/CredentialsChangedNotifier.kt

@@ -76,9 +76,6 @@ class ApplicationPasswordLoginHelperTest : BaseUnitTest() {
     @Mock
     lateinit var wpApiClientProvider: WpApiClientProvider
 
-    @Mock
-    lateinit var credentialsChangedNotifier: CredentialsChangedNotifier
-
     private lateinit var applicationPasswordLoginHelper: ApplicationPasswordLoginHelper
 
     @Before
@@ -95,8 +92,7 @@ class ApplicationPasswordLoginHelperTest : BaseUnitTest() {
             apiRootUrlCache,
             discoverSuccessWrapper,
             crashLogging,
-            wpApiClientProvider,
-            credentialsChangedNotifier
+            wpApiClientProvider
         )
     }
 
@@ -210,7 +206,6 @@ class ApplicationPasswordLoginHelperTest : BaseUnitTest() {
         verify(siteStore).sites
         verify(dispatcherWrapper).updateApplicationPassword(eq(siteModel))
         verify(wpApiClientProvider).clearSelfHostedClient(eq(siteModel.id))
-        verify(credentialsChangedNotifier).notifyChanged(eq(siteModel.id))
     }
 
     @Test