Fix archived_conversations creation migration

app/src/main/kotlin/com/simplemobiletools/smsmessenger/databases/MessagesDatabase.kt

@@ -117,7 +117,7 @@ abstract class MessagesDatabase : RoomDatabase() {
         private val MIGRATION_7_8 = object : Migration(7, 8) {
             override fun migrate(database: SupportSQLiteDatabase) {
                 database.apply {
-                    execSQL("CREATE TABLE archived_conversations (`thread_id` INTEGER NOT NULL PRIMARY KEY,  `deleted_ts` INTEGER NOT NULL)")
+                    execSQL("CREATE TABLE IF NOT EXISTS archived_conversations (`thread_id` INTEGER NOT NULL PRIMARY KEY,  `deleted_ts` INTEGER NOT NULL)")
                 }
             }
         }