fix: add repair job to deleted duplicated cached messages

[st3iny]

This prepares the database to the make the mailbox_id + uid index unique. Currently, there might be some duplicated cached message which are unique. They were most likely inserted twice due to a race condition.

mail/lib/Listener/OptionalIndicesListener.php

Lines 86 to 92 in 8f9310f

	$event->replaceIndex(
	'mail_messages',
	['mail_messages_mb_id_uid'],
	'mail_messages_mb_id_uid_uidx',
	['mailbox_id', 'uid'],
	true
	);

[st3iny]

/backport to stable 3.7

[st3iny]

/backport to stable3.7