EXT-6710 FIXED Corrected 'ItemsShared' notification message and provided logging of 'item shared' message instead of spawning IM session and add message to it.
Details:
1 Corrected 'ItemsShared' notification message.
2 Avoided spawning session on item shared event.
3 Provided logging of item shared message.
4 Provided logging of 'IMSystemMessageTip' notification without opened related IM session.

reviewed by Mike Antipov at https://codereview.productengine.com/secondlife/r/612/

--HG--
branch : product-engine