Copying login keychains between Macs fails on Secure Enclave Macs with Tahoe

On macOS Tahoe, manually copying login keychain files between Macs no longer works for Secure Enclave-equipped Macs because the encryption keys are tied to the source Mac's Secure Enclave and cannot be accessed on the destination Mac. While the keychain password may be correct, the actual decryption keys needed to unlock the keychain's contents are stored in the Secure Enclave and are unavailable when the keychain is moved to another device.