sfos-v0.51 with patches

Changelog:

• Updated to 0.5.1 upstream,
• Applied patches by @ichthyosaurus:
  1. Fix garbled replies to replies due to invalid reply formatting
  2. Fix backup key and filter field being autofilled as logins
  3. Improve legibility of quick reaction emojis when using monochrome fonts
  4. Add "😂" to list of quick reaction emojis
  5. Render audio messages and stickers

element-hq#1202, element-hq#1200, element-hq#1199, element-hq#1198, element-hq#1197, element-hq#1195