Add zero address checks for `L*BitcoinDepositor` initializers #5257

Job	Run time
contracts-detect-changes	6s
contracts-build-and-test	3m 54s
contracts-deployment-dry-run	1m 28s
contracts-format	1m 55s
contracts-slither	2m 17s
contracts-dapp-development-deployment-testnet	0s
contracts-deployment-testnet	0s
contracts-etherscan-verification	0s
	9m 40s

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