* Add expand/collapse UI for reactions
- Adds a CollapsibleFlowLayout for controlling the layout
- Adds tests for this layout and some mocks for testing layouts generally
- Improves the rendering of the reaction buttons which were not pixel perfect
- Adds the UI for the expand collapse buttons including the count of hidden items in the collapsed state.
* Add comment for reactionsCollapsed binding.
* Remove Flow and simplify implementation
- Remove SwiftUI-Flow
- Add strings by importing from Localyse
- Remove count on expand button as requires GeometryReader and can cause loops
- Don't use GeometryReader for hiding reactions with opacity(just put them way off screen for now)
- Fix unit and UI tests
* Address PR comments
- use synthesized inits
- use rows rather than lines for naming flow layout
- other naming improvements
- reactions were already rendered in another ui test, removing my test on favour of those and updating the screenshots for those.
