Update display text in cert notification

- Show DPC app name for PO
- Check user id for DO
- Update notification title for all cases
- update symbols for private resource ssl_ca_cert_warning changed from string to plural
- Pass number of certificate to MonitoringCertInfoActivity

Bug: 25772443
Bug: 18224038
Change-Id: I68db06f55a24879c1d5f532e38b97e2932bf990e