Add event log for content capture

Add event log for content capute connect and set allowlist to help
the debugging.

Some examples:
I cc_connect_state_changed( 1762): [com.google.android.as/com.google
.android.apps.miphone.aiai.app.AiAiContentCaptureService,1]
I cc_set_allowlist: [14,0]

Doesn't have MemoryOnBoot regression for com.google.intelligence.sense
after this change. The reason is caused by the crash when the service
calling set allowlist. This change fixes the NPE when calling set
allowlist, the result is as below:
before: go/cc_eventlog_memtest_before
after: go/cc_eventlog_memtest_after
issue: go/cc_eventlog_memtest_issue

Bug: 233040086
Test: manual. To watch event log
Test: atest CtsContentCaptureServiceTestCases
BYPASS_INCLUSIVE_LANGUAGE_REASON=existing APIs

Change-Id: I9b3a97b808c65902d8ff346e6aa890be852fa598