Increasing length of the datagram for Unix Domain Socket

- address p99 StatsD socket loss issue

Bug: 284508851
Test: atest statsd_test
Test: atest statsd_benchmark
Ignore-AOSP-First: mitigate data loss in Android U
Change-Id: I4124ba8d4d78733eb666073f6d29dfe0c0552c0f
Merged-In: I4124ba8d4d78733eb666073f6d29dfe0c0552c0f