Clean up unread indicator method, variable, and component names

[marcaaron]

Problem

We have some ambiguous naming conflicts that make the ReportActionsView difficult to understand namely...

• "marker badge" is hard to distinguish from the "new marker" since they both are "markers"
• localUnreadActionCount refers to the floating "counter" count and is hard to distinguish from a report's unreadActionCount
• updateUnreadIndicator refers to the "NEW marker" but could refer to any number of "unread indicators"

Solution

Improve the names so this code is easier to understand.