Add rudimentary end-to-end test for meditor and file browser from DLP

[yarikoptic]

As we all failed to catch an obvious bug while reviewing #1706 and that required hotfix #1759 . Could be prevented with a basic test of opening file browser view. I looked at https://github.com/dandi/dandi-archive/tree/master/web/test/src/tests but didn't find any for meditor or file browser. Even if not thorough/sophisticated, I think such smoke tests could be already of notable value.

[dandibot]

🚀 Issue was released in v0.3.72 🚀