Adjust invite animation for Media Viewer

With latest refactorings, the animatin looked like a glitch.
The position of the panel has been adjusted to (a) make the initial
position the same as shown while the progress bar for better continuity,
and (b) make the move more noticeable by increasing the distance the
panel moves.

To test, clear the local storage variable mmv.hasOpenedMetadata

Change-Id: Ie3ed29826fa15bf4c6b38f0fc8bde4bd84563fb9
Merge "Adjust invite animation for Media Viewer"