fix(item-sliding): remove item-sliding-closing class and re-enable gesture when opening sliding item

[rudrakshagarwal4200-ai]

Fixes #29975.

Description of Change

• When an <ion-item-sliding> item is closing (or when close() / closeOpened() is called), setOpenAmount(0, ...) adds the class item-sliding-closing and disables the gesture for 600ms via this.tmr = setTimeout(...). In CSS, .item-sliding-closing ion-item-options applies pointer-events: none.
• If another side is subsequently opened while closing (e.g. calling open('end').then(() => open('start')) or dragging the other direction), setOpenAmount(openAmount, ...) cleared this.tmr, but failed to remove item-sliding-closing or re-enable this.gesture.
• As a result, item-sliding-closing remained on the element indefinitely, leaving options with pointer-events: none and completely unclickable.
• Added a check in setOpenAmount when openAmount !== 0 to remove item-sliding-closing and re-enable this.gesture.
• Added an e2e test verifying that opening the opposite side clears item-sliding-closing.

[vercel]

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