sanitize user input in Conversation/MessageInfo

Certain strings in a sender's name or message snippet could
cause ConversationInfo/MessageInfo objects to become malformed.
Escape the critical '^' (caret) character to prevent any string
input from appearing like a delimiter.

Bug: 7593796
Change-Id: I70266410c738d366be6ec4d6b00413543a9e22db
3 files changed