Fix API in CaptivePortal and ConnectivityManager

- Remove CaptivePortal constructor from SystemApi. This constructor was
   added in Q timeframe and ends up being unnecessary since
   CaptivePortal creation was refactored to ConnectivityService because
   of visibility issues on ICaptivePortal.
 - Rename getAvoidBadWifi to shouldAvoidBadWifi
 - Add permission annotation for shouldAvoidBadWifi

(already merged in internal as:
I09545c00af3519dbf141dd5951b28f49e37b3e80)

Test: flashed, WiFi and captive portal works
Bug: 128935314
Bug: 128935673
Merged-In: I09545c00af3519dbf141dd5951b28f49e37b3e80
Change-Id: I7395d4a4db6a64398a827692aee1956c011873e5

core/java/android/net/CaptivePortal.java

@@ -64,8 +64,6 @@ public class CaptivePortal implements Parcelable {
     private final IBinder mBinder;
 
     /** @hide */
-    @SystemApi
-    @TestApi
     public CaptivePortal(@NonNull IBinder binder) {
         mBinder = binder;
     }

core/java/android/net/ConnectivityManager.java

@@ -4101,9 +4101,12 @@ public class ConnectivityManager {
      * @hide
      */
     @SystemApi
-    public boolean getAvoidBadWifi() {
+    @RequiresPermission(anyOf = {
+            NetworkStack.PERMISSION_MAINLINE_NETWORK_STACK,
+            android.Manifest.permission.NETWORK_STACK})
+    public boolean shouldAvoidBadWifi() {
         try {
-            return mService.getAvoidBadWifi();
+            return mService.shouldAvoidBadWifi();
         } catch (RemoteException e) {
             throw e.rethrowFromSystemServer();
         }

core/java/android/net/IConnectivityManager.aidl

@@ -182,7 +182,7 @@ interface IConnectivityManager
     void startCaptivePortalApp(in Network network);
     void startCaptivePortalAppInternal(in Network network, in Bundle appExtras);
 
-    boolean getAvoidBadWifi();
+    boolean shouldAvoidBadWifi();
     int getMultipathPreference(in Network Network);
 
     NetworkRequest getDefaultRequest();

services/core/java/com/android/server/ConnectivityService.java

@@ -3470,8 +3470,12 @@ public class ConnectivityService extends IConnectivityManager.Stub
         return mMultinetworkPolicyTracker.getAvoidBadWifi();
     }
 
-    @Override
-    public boolean getAvoidBadWifi() {
+    /**
+     * Return whether the device should maintain continuous, working connectivity by switching away
+     * from WiFi networks having no connectivity.
+     * @see MultinetworkPolicyTracker#getAvoidBadWifi()
+     */
+    public boolean shouldAvoidBadWifi() {
         if (!checkNetworkStackPermission()) {
             throw new SecurityException("avoidBadWifi requires NETWORK_STACK permission");
         }