Update bubble style to align with server

[SystemKeeper]

• Ref Update bubble style #2269
• Ref feat(chat): split own and other messages spreed#16273

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Todos

• Author name outside of bubble
• Own messages should show the own actor name
  • Bonus points: In "tablet view" own messages could show the own avatar next to the message and skip the name above it instead
• Posting time should be at the "bottom" of the message in the line of reactions (if possible)

[SystemKeeper]

This is done for now.