Collect connectivity diagnostics related information from DSRS

1. Collect validation and network probe results
2. Sending notification when data stall recovered

Bug: 319601607
Test: Successfully test on Pixel device with simulate data stall environment
Change-Id: Ifbbf20ac5f273fb5cd452f79a055b567bbfe04c6
diff --git a/flags/data.aconfig b/flags/data.aconfig
index 3beb016..a265260 100644
--- a/flags/data.aconfig
+++ b/flags/data.aconfig
@@ -117,4 +117,11 @@
   namespace: "telephony"
   description: "This flag is for internal implementation to handle reconnect request from QNS in telephony FWK."
   bug: "319520561"
+}
+
+flag {
+  name: "dsrs_diagnostics_enabled"
+  namespace: "telephony"
+  description: "Enable DSRS diagnostics."
+  bug: "319601607"
 }
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