🪲 Fix lz:deploy task not being able to find external deployments

[janjakubnanista]

In this PR

• The run function on DeploymentsExtension would clear its database if resetMemory wasn't explicitly set to false. This also cleared the external deployments and made EndpointV2 deployment not accessible in the deploy script.
• The fix is very tricky to test so I introduced two user tests that basically check that nox hardhat lz:deploy will not fail on a missing deployment. First I made these tests fail (see here) and then introduced a fix. The trickiness of this test is the fact that we'd need to completely erase the runtime between every test - something we might still want to do. In the meantime I covered the task with basic tests and made sure that from the users' perspective the deploy task works [*]
• Added a small fix - The --ci should be a CLI flag, not a parameter that takes a boolean value

[*] Well what we do is we test that the deploy task fails, but it fails on insufficient funds. It might be nice to add a nightly test that uses a funded testnet mnemonic / private key to actually run all the deployment and wiring