[dagit] Handle WS issue in CSP for Safari

Summary: The connect-src: 'self' configuration in the CSP is failing in Safari, which is rejecting WebSocket connections. Add ws: and wss:, which is really unfortunate. I'd like to fix Safari temporarily with this, but would really prefer a better long-term solution than this.

Test Plan: Test dev and prod builds in Chrome, Firefox, Safari. Verify that Dagit loads and performs WS connections correctly.

Reviewers: bengotow, dgibson, max

Reviewed By: dgibson

Differential Revision: https://dagster.phacility.com/D9012