Add app settings to backups

This should be compatible with Aniyomi's implementation.
Related to #1857

Co-authored-by: jmir1 <jmir1@users.noreply.github.com>

core/src/main/java/tachiyomi/core/preference/AndroidPreference.kt

@@ -12,6 +12,7 @@ import kotlinx.coroutines.flow.filter
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.onStart
 import kotlinx.coroutines.flow.stateIn
+import tachiyomi.core.util.system.logcat
 
 sealed class AndroidPreference<T>(
     private val preferences: SharedPreferences,
@@ -29,7 +30,13 @@ sealed class AndroidPreference<T>(
     }
 
     override fun get(): T {
-        return read(preferences, key, defaultValue)
+        return try {
+            read(preferences, key, defaultValue)
+        } catch (e: ClassCastException) {
+            logcat { "Invalid value for $key; deleting" }
+            delete()
+            defaultValue
+        }
     }
 
     override fun set(value: T) {

core/src/main/java/tachiyomi/core/preference/AndroidPreferenceStore.kt

@@ -60,6 +60,10 @@ class AndroidPreferenceStore(
             deserializer = deserializer,
         )
     }
+
+    override fun getAll(): Map<String, *> {
+        return sharedPreferences.all ?: emptyMap<String, Any>()
+    }
 }
 
 private val SharedPreferences.keyFlow

core/src/main/java/tachiyomi/core/preference/PreferenceStore.kt

@@ -20,6 +20,8 @@ interface PreferenceStore {
         serializer: (T) -> String,
         deserializer: (String) -> T,
     ): Preference<T>
+
+    fun getAll(): Map<String, *>
 }
 
 inline fun <reified T : Enum<T>> PreferenceStore.getEnum(