Reduce AsyncHttpTransport timeout when closing to prevent ANRs

[romtsn]

Description

https://github.com/getsentry/sentry-java/blob/2718fc84e3251bcfb233f6a7ff2775e690820563/sentry/src/main/java/io/sentry/transport/AsyncHttpTransport.java#L143C53-L143C53

This is causing ANRs on Android when Sentry.close() is called, we should reduce it to 4s max to prevent ANRs. At least when this is called on the main thread.

[romtsn]

Closed by #2879