refactor: replace deprecated Popover with Modal in SetApproveForAllWarning

[chiliec]

Summary

• Migrates SetApproveForAllWarning (the NFT set-approval-for-all security warning) from the deprecated ui/components/ui/popover Popover to the component-library Modal (Modal/ModalOverlay/ModalContent/ModalHeader/ModalBody/ModalFooter), matching the pattern already used by bridge-alert-modal
• Adds isOpen/onClose props to drive the Modal (onClose defaults to onCancel)
• Existing BEM classNames are preserved, so styling is unchanged aside from the Modal's own built-in behavior (adds a close button in the header, top-aligns the dialog instead of vertically centering it — same as other Modal call sites in the app)

Part of #19555.

CHANGELOG entry: Replace deprecated Popover with Modal from the component-library in the SetApproveForAllWarning confirmation dialog.

Test plan

• yarn lint:changed passes
• Verified via Storybook (SetApproveForAllWarning story) that the dialog renders correctly with no functional change to the approve/reject actions
• Compared before (Popover, main) and after (Modal, this branch) screenshots — only difference is the Modal's standard chrome (close button, top alignment), consistent with bridge-alert-modal

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Note

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[chiliec]

[chiliec]

I have read the CLA Document and I hereby sign the CLA