If I restore my electrum wallet from seed will I lose my pending transaction
Your transaction is out in the network. It doesn't need to be rebroadcasted by your wallet (which probably doesn't do this anyways all by itself) in order to survive. It just needs to be in someone's mempool. Deleting your wallet will not stop the transaction. When you delete your wallet and restore it with your seed, you will have access to the same money you have access to now, but the notes you may or may not have stored in your Electrum wallet will be gone.