Report Widgets Core: Add support for hiding the dropdown
Context
For &7066 (closed) we want to hide the collapse dropdown when fetchCollapsedData
fails.
Thus we need to add support for hiding the dropdown.
Required reading
Please ensure that:
- all the code written implements the rules of Accessibility https://design.gitlab.com/regions/merge-request-reports#accessibility
- you're familiar with the overall goal https://www.figma.com/file/qEddyqCrI7kPSBjGmwkZzQ/Component-library?node-id=38193%3A30482
Task
Add support for hiding the collapse dropdown and its border.
Edited by Jiaan Louw