Catch errPrivateRepoPublicSourcegraph when resolving code views

Created by: lguychard

ERPRIVATEREPOPUBLICSOURCEGRAPHCOM is the top reported exception in Sentry/browser-extension, while it typically is an internal error that should be handled.

All stacks I looked at had were related to the same scenario: trying to resolve diff code views on Github PRs, where resolveDiffFileInfo() calls resolveRev() to try and resolve the head and base revisions.

To avoid undesired reporting of this exception on sentry, this PR adds a catchError() block to the codeViews observable, so that in such cases we simply ignore the code view without uncaught exceptions.