Minor UI improvements and bug fixes.

Improvements

• [SCSD-535] Updated desktop icons.

Bug Fixes

• [SI-2823] Corrected the wording for the message forwarded alert. Currently it needs to simply say “Someone” forwarded a message.
• [SCSD-522] Link previewing had to be disable due to an issue in a related library.
• [SCSD-523] Forward alerts are now recognised and screenshots are sent to the group and not the individual.
• [SCSD-531] Burnt messages received when offline would still appear on the desktop.