Improve Activity Panel rendering performance
The Activity Panel can renders all Translation History items including revisions and comments.
If a single textflow has a significant amount of work done on it, rendering all of its Activity items can cause performance issues.
Though this will not generally be the case for most trans units, it presents some user experience problems as the translation history is fetched when moving to a new text flow, creating revisions and comments.
We should also limit unnecessary calls to fetchTranslationHistory when new revisions or comments are created if the Activity Panel is not displayed ( When the Glossary Panel is selected or the sidebar is hidden entirely).
Paginate the Activity Panel's Translation History items, re-using the Pager component.
Track and display the visible state of the Activity Panels Tab in the Control Header.
Create a condition to only call fetchTranslationHistory if the Activity Panel is active.