* Update react-overlays to latest version
* Fix breaking changes in dropdown menus
* Use react-overlays built-in arrow positioning feature
* Re-implemented `.dropdown-menu__arrow` to have a defined width and height to improve positioning
* Moved wrapping div (`.dropdown-menu` from `DropdownMenu` to `Dropdown`)
* Wrap button in a span to solve issue with ref
* Temporarily remove animations
* Fix breaking changes in emoji picker
* Wrap EmojiPickerMenu in a div where react-overlays’ ref is added
* Fix breaking changes in language dropdown
* Fix breaking changes in privacy dropdown
* Fix breaking changes in search form
* Add animations back using `@keyframes`
* Fix arrow color in light theme
* Fix linting issue
* Remove unused `mounted` state
* Remove `placement` state from components and redux
And remove the placement state from props of the menu components.
* Remove abolution position to fix flip issue
* Remove z-index to fix modals and overlay positions
* Fix lint issues
* Set placement in privacy and language components
Copy the placement state into the `PrivacyDropdown` and `LanguageDropdown` components, to apply correct styling to the buttons depending on which placement the Overlay has.
* Move `placement` state to correct component
* Remove pointer events on the entire UI when a dropdown menu is open
This prevents operations to change the location of the menu such as
scrolling.
* Fix mistake from merge
