Multiselect component

[sahariko]

Main Change

Add support for multiple values to our <Dropdown> component, via the following new props:

• multi - When passed, will render selected options as chips.
• multiline - When passed, and the component is constrained with a specific width, will cause it to drop line instead of displaying a counter of unrendered chips.
• onOptionRemove - Will be called whenever a chip’s “X” is clicked.
• onOptionSelect - Will be called whenever an option is clicked inside the menu.
• onClear - Will be called whenever the generic clear button is clicked.

Additional Changes

Infrastructure

• Add support for CSS modules.

<Dropdown>

• Separate test driver to its own file.
• Remove unused (and non-existent) isOpen prop from <Menu>.

<Chips>

• Enable rendering without animations (looks bad in the context of multiselect).
• Support passing data-testid.

<Counter>

• Enable rendering without animations (looks bad in the context of multiselect).
• Support new onMouseDown prop, needed to prevent <Dropdown> from opening the menu when the counter is clicked.

<Dialog>

• Fix bug with open prop, which caused it to be “ignored” when the component’s internal state changes.
• Move default tooltip arrow styling from <Tooltip> to this component.

<Icon>

• Support passing data-testid.