Refactor tethering utility methods

This is no-op refactoring to extract tethering utility methods
to a standalone file, and split setup and clean up process
to allow new test cases can perform custom verifications.

Also, this CL makes connectToWifi returns NetworkHandle for later use.

Test: m connectivity_multi_devices_snippet && \
      atest CtsConnectivityMultiDevicesTestCases:ConnectivityMultiDevicesTest
Bug: 335368434
Change-Id: Ib0df28107fd09b573db1e51ff624d0f027bda23d
diff --git a/tests/cts/multidevices/snippet/ConnectivityMultiDevicesSnippet.kt b/tests/cts/multidevices/snippet/ConnectivityMultiDevicesSnippet.kt
index 543dc03..8805edd 100644
--- a/tests/cts/multidevices/snippet/ConnectivityMultiDevicesSnippet.kt
+++ b/tests/cts/multidevices/snippet/ConnectivityMultiDevicesSnippet.kt
@@ -21,7 +21,6 @@
 import android.content.pm.PackageManager.FEATURE_TELEPHONY
 import android.content.pm.PackageManager.FEATURE_WIFI
 import android.net.ConnectivityManager
-import android.net.Network
 import android.net.NetworkCapabilities.NET_CAPABILITY_VALIDATED
 import android.net.NetworkCapabilities.TRANSPORT_WIFI
 import android.net.NetworkRequest
@@ -93,7 +92,7 @@
     // Suppress warning because WifiManager methods to connect to a config are
     // documented not to be deprecated for privileged users.
     @Suppress("DEPRECATION")
-    fun connectToWifi(ssid: String, passphrase: String, requireValidation: Boolean): Network {
+    fun connectToWifi(ssid: String, passphrase: String): Long {
         val specifier = WifiNetworkSpecifier.Builder()
             .setBand(ScanResult.WIFI_BAND_24_GHZ)
             .build()
@@ -126,7 +125,7 @@
                 // Remove double quotes.
                 val ssidFromCaps = (WifiInfo::sanitizeSsid)(it.caps.ssid)
                 ssidFromCaps == ssid && it.caps.hasCapability(NET_CAPABILITY_VALIDATED)
-            }.network
+            }.network.networkHandle
         }
     }