fix(input-accessory): improved positioning and state handling

[NathanWalker]

Improves the iOS input accessory bar's reliability and user experience, especially when dismissing the keyboard and managing the accessory view's lifecycle.

Accessory Bar & Keyboard Dismissal Reliability:

• Added a robust mechanism to keep the accessory bar visible when dismissing the keyboard by transferring first responder status from the text input back to the accessory view, preventing the input bar from being removed unexpectedly. This includes handling scenarios where the keyboard is dismissed via both the plugin and system APIs. [1] [2] [3]

Accessory Bar Layout & Safe Area Handling:

• Refined the logic for calculating and updating the accessory bar's bottom inset, ensuring it sits flush above the keyboard when visible and includes safe area padding only when the keyboard is hidden. This prevents visual jumps and ensures consistent positioning.

ScrollView & Content Inset Adjustments:

• Improved the calculation of scroll view insets and content offset to prevent unwanted jumps during keyboard transitions, especially when switching first responder between the text input and accessory bar.

Cleanup and Memory Management:

• Enhanced cleanup logic to properly remove observers and references, ensuring no memory leaks or unwanted behavior after the accessory bar is destroyed.