Add AppTP blocklist stat pixel (#6069)

Task/Issue URL:
https://app.asana.com/1/137249556945/project/1202096681738622/task/1210212720766789?focus=true

### Description
Ditto

### Steps to test this PR
- [ ] Clean install from this branch
- [ ] Start app
- [ ] Verify `m_atp_report_blocklist_stats_d` pixel is sent with proper
blocklist stats

Author: nshuba

app-tracking-protection/vpn-impl/src/main/java/com/duckduckgo/mobile/android/vpn/blocklist/AppTrackerListUpdateWorker.kt

@@ -29,6 +29,7 @@ import com.duckduckgo.app.lifecycle.MainProcessLifecycleObserver
 import com.duckduckgo.common.utils.DispatcherProvider
 import com.duckduckgo.di.scopes.AppScope
 import com.duckduckgo.mobile.android.vpn.di.AppTpBlocklistUpdateMutex
+import com.duckduckgo.mobile.android.vpn.pixels.DeviceShieldPixels
 import com.duckduckgo.mobile.android.vpn.store.VpnDatabase
 import com.duckduckgo.mobile.android.vpn.trackers.AppTrackerMetadata
 import com.squareup.anvil.annotations.ContributesMultibinding
@@ -56,10 +57,23 @@ class AppTrackerListUpdateWorker(context: Context, workerParameters: WorkerParam
     @AppTpBlocklistUpdateMutex
     lateinit var mutex: Mutex
 
+    @Inject
+    lateinit var deviceShieldPixels: DeviceShieldPixels
+
     override suspend fun doWork(): Result {
         return withContext(dispatchers.io()) {
             val updateBlocklistResult = mutex.withLock {
-                updateTrackerBlocklist()
+                val res = updateTrackerBlocklist()
+
+                // Report current blocklist status after update
+                deviceShieldPixels.reportBlocklistStats(
+                    mapOf(
+                        "blocklist_etag" to vpnDatabase.vpnAppTrackerBlockingDao().getTrackerBlocklistMetadata()?.eTag.toString(),
+                        "blocklist_size" to vpnDatabase.vpnAppTrackerBlockingDao().getTrackerBlockListSize().toString(),
+                    ),
+                )
+
+                res
             }
 
             val success = Result.success()

app-tracking-protection/vpn-impl/src/main/java/com/duckduckgo/mobile/android/vpn/pixels/DeviceShieldPixelNames.kt

@@ -184,6 +184,7 @@ enum class DeviceShieldPixelNames(override val pixelName: String, val enqueue: B
     ATP_REPORT_ANY_LOCAL_ADDR_DNS_SET_DAILY("m_atp_report_anylocal_dns_error_d"),
     ATP_REPORT_DNS_SET_ERROR("m_atp_report_dns_error_c"),
     ATP_REPORT_DNS_SET_ERROR_DAILY("m_atp_report_dns_error_d"),
+    ATP_REPORT_BLOCKLIST_STATS_DAILY("m_atp_report_blocklist_stats_d"),
 
     ATP_DID_SHOW_PROMOTE_ALWAYS_ON_DIALOG_UNIQUE("m_atp_imp_promote_always_on_dialog_u"),
     ATP_DID_SHOW_PROMOTE_ALWAYS_ON_DIALOG_DAILY("m_atp_imp_promote_always_on_dialog_d"),

app-tracking-protection/vpn-impl/src/main/java/com/duckduckgo/mobile/android/vpn/pixels/DeviceShieldPixels.kt

@@ -319,6 +319,8 @@ interface DeviceShieldPixels {
     fun reportAnylocalDnsError()
     fun reportGeneralDnsError()
 
+    fun reportBlocklistStats(payload: Map<String, String>)
+
     /**
      * Will fire when the user is interacting with the Promote Always On Dialog
      */
@@ -756,6 +758,10 @@ class RealDeviceShieldPixels @Inject constructor(
         firePixel(DeviceShieldPixelNames.ATP_REPORT_DNS_SET_ERROR)
     }
 
+    override fun reportBlocklistStats(payload: Map<String, String>) {
+        tryToFireDailyPixel(DeviceShieldPixelNames.ATP_REPORT_BLOCKLIST_STATS_DAILY, payload)
+    }
+
     override fun didEnableAppProtectionFromDetail() {
         firePixel(DeviceShieldPixelNames.ATP_DID_ENABLE_APP_PROTECTION_FROM_DETAIL)
     }

app-tracking-protection/vpn-store/src/main/java/com/duckduckgo/mobile/android/vpn/dao/VpnAppTrackerBlockingDao.kt

@@ -44,6 +44,9 @@ interface VpnAppTrackerBlockingDao {
     @Query("DELETE from vpn_app_tracker_blocking_list")
     fun deleteTrackerBlockList()
 
+    @Query("SELECT COUNT(*) FROM vpn_app_tracker_blocking_list")
+    fun getTrackerBlockListSize(): Int
+
     @Query("DELETE FROM vpn_app_tracker_blocking_app_packages")
     fun deleteAppPackages()