Fix recovery of stats data from previous input while using

ProtoOutputStream

- Specify the length of message to avoid libprotoutil from thinking that
we are trying to write bool
- We only attach the previous dump file to the upload file where config
key matches
- Store ConfigMetricsReport (instead of ConfigMetricsReportList) onto
disk
- Stop use stack after scope in StorageManager
- Migrate UidMap to use ProtoOutputStream and renaming variables to
prevent confusion

Bug: 74021554
Bug: 75968524
Test: manual test, statsd_test, CTS tests
Change-Id: Iedf52633d7f5b985f5a934a3fb5a0c3c3b2e7fd1