Add dumpsys to Telecom analytics output

Output a Base64-encoded proto when Telecom's dumpsys is called with the
"analytics" argument, with an option to clear analytics at the same
time. This is in preparation for moving Connectivity Metrics to GmsCore.

Also fixed a bug in video call analytics and adds a test for it.

Bug: 30600318

Change-Id: I567d769123d78b7e5e2b9e8865fccf36f4f30fae