feat(ux): page turning on button pressed if long-press chapter skip is disabled (#451)

## Summary

* If long-press chapter skip is disabled, turn pages on button pressed,
not released
* Makes page turning snappier
* Refactors MappedInputManager for readability

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### AI Usage

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Co-authored-by: Dave Allie <dave@daveallie.com>

src/MappedInputManager.h

@@ -25,5 +25,6 @@ class MappedInputManager {
 
  private:
   InputManager& inputManager;
-  decltype(InputManager::BTN_BACK) mapButton(Button button) const;
+
+  bool mapButton(Button button, bool (InputManager::*fn)(uint8_t) const) const;
 };