Add frontend testing for react components

[SaptakS]

We already have some basic react components in the filter sidebar and charts. So I think we can start adding tests to catch some of the errors by JS unittesting. We might need to add further integration tests (or end-to-end tests). I think we can use jest and react-testing-library to write most of the unittest (it technically does integration tests for react components since it actually checks the dom generated, but not an E2E test with the backend). For an E2E testing further we can consider selenium or cypress maybe.

I think the deliverable for this issue can be to test all the react components used in the sidebar to prevent issues like #1546