Update the UI code to proprely show the cancelListing button, Changed the...

Update the UI code to proprely show the cancelListing button, Changed the rendering condition to isSeller && isListed instead of isOwner && isListed, since if the NFT isListed it will be sent on escrow to the Contract Address, which means that the currently connected User won't be the owner even if he is the Seller (formely the owner)