Throwing Exception without lastServerResponse

**Is your feature request related to a problem? Please describe.**
Whenever the connected MTA unable to provide 220 for welcome message, the last server response is not included in the Messaging Exception. This sometimes makes us difficult to debug the issue (Mostly when our IP address is listed (or) when the MTA is unable to serve any requests)

**Describe the solution you'd like**
Instead of providing the return code, we can construct the Exception with lastServerResponse

**Describe alternatives you've considered**
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**Additional context**
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No file or test is named in the issue. Start by locating the Java code that handles the MTA welcome response and constructs the MessagingException, then find its related tests. Done means a non-220 welcome failure includes the last server response in the exception.

Written by the indexing model from the issue text.