Export Metadata pre-populates wrong query if you enter via Media menu

[bctcvai]

If you use the media menu to enter the export dashboard tool, it populates a query for the metadata belonging to the section that media is in vs. just that media.

Suggested fix: If one enters the export from the Media menu, it should pre-populate a media filter; if it entered via the section menu, it should pre-populate a section filter, if it entered via the project-level menu item no filters should be populated.