ScriptMimeMessage#addPart should support BodyPart

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Prerequisites

• The student will need to have a Jira account, if it's not the case you can signup here
• The student will also need a https://www.github.com account. You might also want to take a look at Git and GitHub interface documentations.

• Assign yourself to the Jira issue

Issue

The API ScriptMimeMessage#addPart should allow getting a BodyPart directly in input (which essentially means not touching it).

Expected Outcome

• The student must commit the changes and create a pull request on https://github.com/xwiki/xwiki-platform
  • The summary of the Pull Request must have a first line matching the JIRA issue following by a colon and then the title of this issue
  • Add a comment in the jira issue mentioning your pull request and provide a link to it

Links

• https://github.com/xwiki/xwiki-platform/blob/master/xwiki-platform-core/xwiki-platform-mail/xwiki-platform-mail-send/xwiki-platform-mail-send-default/src/main/java/org/xwiki/mail/script/ScriptMimeMessage.java#L107

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