Support edited messages in Actiance Export

Description

When a message or post is edited, we need to reference that it was edited and reference the original post contents and who had access.

QA Test Steps

None

Status

Mana

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Assignee

Unassigned

Reporter

Katie Wiersgalla

Epic Link

None

Fix versions

None

Mattermost Team

Platform

Sprint

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Labels

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GitHub Issue

None