[IntrusionLogging] Fix STORED_EVENTS_SIZE_LIMIT batch limit

STORED_EVENTS_SIZE_LIMIT is too high for the current batch
rate, as events are only batched at Network or DNS events.

Lowering batch limit to 4 to allow for the transportation and
storage of network events.

Bug: 416710031
Test: atest android.security.cts.IntrusionDetectionManagerTest
Ignore-AOSP-First: security feature
Flag: EXEMPT: bugfix in localized component
Change-Id: I1d76c7f5676e917999f758afea91406b08b85408