Better handling of network errors/timeouts

[f1ames]

While testing the extension I stumbled upon few cases where there were some minor issues due to connectivity problems:

1. There is a "blinking" of local policy sometimes when changing monokle.project (when fetching new policy takes longer).
2. Occasional Monokle: fetchPolicyFiles TypeError: Cannot read properties of null (reading 'accessToken') error (which causes issues with policy sync for a single sync, usually fixed on next sync).
3. Occasional Failed to parse '/home/kkrzton/Workspace/kubeshop/monokle-vsc/.monokle/ec5a1a57115b2b8cf9eeee71feafcb42.validation.json' error - looks like it's related to API timing out and I think extension removes policy file in such cases as outdated (but needs further investigation).

All above are related to connectivity problems and how does are handled. It doesn't cause any major issues with the extension running but there is a place for improvement.

[f1ames]

Let's also revisit catch-all handler for TypeErrors added in #61 as described in #61 (comment).