fix: show installed extensions when manifest cannot be reached

[motorina0]

Report from @callebtc:

I noticed a bug in the extension manager: if the internet connection doesn't work (or possibly if the github token is invalid), lnbits doesn't load up any extensions at all. there should probably be some sort of timeout in during which the extension manifest is polled and if it fails, the extensions should still be visible in the extension manager. I've noticed this because I had a firewall on that silently blocked requests from lnbits and no extensions showed up even though I had them installed.

The logic was there, but due to a bug the wrong filtering took place.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (62dec11) 59.26% compared to head (73ce1ae) 59.26%.

Additional details and impacted files

@@           Coverage Diff           @@
##              dev    #2261   +/-   ##
=======================================
  Coverage   59.26%   59.26%           
=======================================
  Files          60       60           
  Lines        9026     9027    +1     
=======================================
+ Hits         5349     5350    +1     
  Misses       3677     3677           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.