Add metrics constant for Managed provisioning

Add metric constants to track DPC package name and DPC Installed from
play or not. These will be logged from Managed provisioning.

Bug: 31425628
Bug: 31426019
Change-Id: Ifc9a10d428a40006abfbab35ea455f95c02a14de

proto/src/metrics_constants.proto

@@ -2279,6 +2279,13 @@ message MetricsEvent {
     // OPEN: Settings > Security > Device administrators
     DEVICE_ADMIN_SETTINGS = 516;
 
+    // ACTION: Managed provisioning was launched to set this package as DPC app.
+    // PACKAGE: DPC's package name.
+    PROVISIONING_DPC_PACKAGE_NAME = 517;
+
+    // ACTION: Managed provisioning installed DPC from play or other source.
+    PROVISIONING_DPC_INSTALLED_FROM_PLAY = 518;
+
     // ---- End O Constants, all O constants go above this line ----
 
     // Add new aosp constants above this line.