Allow inclusion of _IGNORED_LOGGERS in breadcrumbs in LoggingIntegration

I am trying to investigate some http connection pooling issues when making a lot of http requests.

I'm getting a lovely sentry report on the failures, but with 'Pool is closed' errors I **really** want to see DEBUG logs from urllib3 in my breadcrumbs.

So, I tried setting up `LoggingIntegration(level=logging.DEBUG)` and `logging.getLogger("urllib3").setLevel(logging.DEBUG)`

But I see nothing.

And, then I see [_IGNORED_LOGGERS](https://github.com/getsentry/sentry-python/blob/ed4ba68cad42ebfbab162b37bf7edad25ebeae55/sentry_sdk/integrations/logging.py#L34) in that LogginIntegration and the reasons why:
* https://github.com/getsentry/sentry-python/issues/788
* https://github.com/getsentry/sentry-python/issues/655

Which are great reasons. But, do those reasons really apply to breadcrumbs?

I appreciate how an error in sending a sentry event over urllib3 is going to create another event, ad infinitum. But (especially with `MAX_BREADCRUMBS` as some protection) is it safe to have `_IGNORED_LOGGERS` apply to `_handler` but not apply to `_breadcrumb_handler` ?

In fact, if there was any urllib3 logging output on the attempt to send the issue, those breadcrumbs would be added to the event that won't be fired because _handler is still adhering to IGNORED_LOGGERS