[In a previous PR](https://github.com/twentyhq/twenty/pull/5008) I was
fixing dark mode by calling useTheme in AppErrorBoundary while there was
actually no parent ThemeProvider. This was causing a bug when an error
was actually intercepted by AppErrorBoundary because theme was empty.
Now I am providing the error theme in GenericErrorFallback, fallbacking
to THEME_LIGHT as it can be called from outside a ThemeProvider (as it
is the case today), but also reading into ThemeProvider in case we end
up using this component in a part of the application where it is
available, not to necessarily use THEME_LIGHT.
## How was it tested?
with @thaisguigon
Locally (dark mode works + error mode works (throwing an error in
RecoilDebugObserver))
3e60c0050c