Migrate some RxSharedPreferences to FlowSharedPreferences

app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsSecurityController.kt

@@ -9,9 +9,15 @@ import eu.kanade.tachiyomi.util.preference.intListPreference
 import eu.kanade.tachiyomi.util.preference.summaryRes
 import eu.kanade.tachiyomi.util.preference.switchPreference
 import eu.kanade.tachiyomi.util.preference.titleRes
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.onEach
 
 class SettingsSecurityController : SettingsController() {
 
+    private val uiScope = CoroutineScope(Dispatchers.Main)
+
     override fun setupPreferenceScreen(screen: PreferenceScreen) = with(screen) {
         titleRes = R.string.pref_category_security
 
@@ -36,8 +42,10 @@ class SettingsSecurityController : SettingsController() {
                 defaultValue = "0"
                 summary = "%s"
 
-                preferences.useBiometricLock().asObservable()
-                        .subscribeUntilDestroy { isVisible = it }
+                isVisible = preferences.useBiometricLock().get()
+                preferences.useBiometricLock().asFlow()
+                    .onEach { isVisible = it }
+                    .launchIn(uiScope)
             }
         }