Make unit test output friendlier

[ssg]

yarn test outputs a huge chunk of stack trace and console error while running unit tests although the tests pass in the end:

Although that's expected, a successful unit test run shouldn't output anything at all and devs should be seeing only the green lights. This change mocks the expected console error as it's not needed in the output. The unit test output looks much more pleasing and easy on the eye like this:

This change aims to reduce developer friction and blidness to actual errors in the future.