Suppress unchecked cast for PreferenceHelper#observe

I know it's not great but it works for now

app/src/main/java/com/wbrawner/simplemarkdown/utility/PreferenceHelper.kt

@@ -47,6 +47,7 @@ class AndroidPreferenceHelper(context: Context, private val coroutineScope: Coro
         }
     }
 
+    @Suppress("UNCHECKED_CAST")
     override fun <T> observe(preference: Preference): StateFlow<T> = states[preference]!!.asStateFlow() as StateFlow<T>
 }