Custom Message-ID header is being overridden by the API generated unique ID

[venkatsc]

Describe the bug Custom Message-ID header is being overridden by the API To Reproduce Steps to reproduce the behavior: Set message-id header <[email protected]> and send out the mail

Expected behavior The message header should be message-id: <[email protected]>

Additional context Seems, message-id being set to generated unique-id irrespective of headers set by API user. https://github.com/eclipse-ee4j/mail/blob/4c092797479f6fb05576e723a6855a7e116ed027/mail/src/main/java/javax/mail/internet/MimeMessage.java#L2210 generated message id should be used only when if (getHeader("Message-ID") == null)

Could not verify the above fix due to https://github.com/eclipse-ee4j/mail/issues/431