mattermost update to 10.6.1-bb.5

Package Merge Request

Package Changes

https://repo1.dso.mil/big-bang/product/packages/mattermost/-/blob/10.6.1-bb.5/CHANGELOG.md

Package MR

big-bang/product/packages/mattermost!301 (merged)

For Issue

Closes big-bang/product/packages/mattermost#203 (closed)

Upgrade Notices

N/A