Move ACTION_CLEAR_DNS_CACHE to ConnectivityManager

- As API review feedback, move ACTION_CLEAR_DNS_CACHE form Intent
  to ConnectivityManager.

- Rename to "android.net.action.CLEAR_DNS_CACHE" because of lint
  suggestion.
frameworks/base/packages/Connectivity/framework/src/android/net/
ConnectivityManager.java:449: error: Inconsistent action value;
expected `android.net.action.CLEAR_DNS_CACHE`, was
`android.intent.action.CLEAR_DNS_CACHE` [ActionValue]

Bug: 183937999
Test: atest FrameworksNetTests
Test: atest ActivityTaskManagerServiceTests
Test: atest android.permission2.cts.PermissionPolicyTest
Test: atest CtsNetTestCases
Change-Id: Iae8aa0ba10dfc7581f0cfaab82643edbee789e2f
diff --git a/framework/api/module-lib-current.txt b/framework/api/module-lib-current.txt
index 513b630..8dfdd61 100644
--- a/framework/api/module-lib-current.txt
+++ b/framework/api/module-lib-current.txt
@@ -26,6 +26,7 @@
     method @RequiresPermission(anyOf={android.Manifest.permission.MANAGE_TEST_NETWORKS, android.Manifest.permission.NETWORK_STACK}) public void simulateDataStall(int, long, @NonNull android.net.Network, @NonNull android.os.PersistableBundle);
     method @RequiresPermission(anyOf={android.Manifest.permission.NETWORK_SETTINGS, android.Manifest.permission.NETWORK_STACK, android.net.NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK}) public void startCaptivePortalApp(@NonNull android.net.Network);
     method public void systemReady();
+    field public static final String ACTION_CLEAR_DNS_CACHE = "android.net.action.CLEAR_DNS_CACHE";
     field public static final String ACTION_PROMPT_LOST_VALIDATION = "android.net.action.PROMPT_LOST_VALIDATION";
     field public static final String ACTION_PROMPT_PARTIAL_CONNECTIVITY = "android.net.action.PROMPT_PARTIAL_CONNECTIVITY";
     field public static final String ACTION_PROMPT_UNVALIDATED = "android.net.action.PROMPT_UNVALIDATED";