[Web] Refactor Touchable not to rely on GestureDetector

[j-piasecki]

Description

• ActionType.NONE is added on the JS side; the web GestureHandler skips sendEvent dispatch for handlers attached with it.
• GestureHandlerButton.web.tsx now creates and attaches its own NativeViewGestureHandler when handlerTag is set (mirroring the native platforms) and drops it on unmount.
• The web NativeViewGestureHandler runs the same press state machine (including the long-press timer) when it manages a button, dispatching press events as DOM CustomEvents (gh:buttonPress etc.). The button listens for these and forwards them to the onButton* callbacks; managed buttons no longer drive pressed state from their own pointer handlers.
• Touchable.web.tsx is deleted — web now uses the shared Touchable implementation.
• Also fixes the web GestureHandler registering event listeners for initially disabled handlers (config is applied before attachment, so the enabled-change path never ran) — covered by a new unit test.

Test plan

Existing tests in the Example app