im: display bestId instead of uri in header bar

The bestId is the preferred way as it ensures that we display the
registered name instead of the full RingID when the former is
available.

Change-Id: If1981076a46835685dce82c07e8b8bc22336a770
Reviewed-by: Guillaume Roguez <guillaume.roguez@savoirfairelinux.com>

src/ConversationVC.mm

@@ -115,7 +115,7 @@
 
                          [contactMethodsPopupButton removeAllItems];
                          for (auto cm : contactMethods) {
-                             [contactMethodsPopupButton addItemWithTitle:cm->uri().toNSString()];
+                             [contactMethodsPopupButton addItemWithTitle:cm->bestId().toNSString()];
                          }
 
                          BOOL isSMultipleCM = (contactMethods.length() > 1);