Fix CTS usages of @hide WifiSsid

Migrate to WifiInfo.getSSID() and ScanResult.SSID.

Bug: 144036594
Test: atest android.net.wifi.cts.ScanResultTest
Change-Id: I402978d9455b0ce9e7dbcdb90836f7b0efa0fdc5
diff --git a/tests/cts/net/src/android/net/wifi/cts/ScanResultTest.java b/tests/cts/net/src/android/net/wifi/cts/ScanResultTest.java
index 9bd1226..3347cb6 100644
--- a/tests/cts/net/src/android/net/wifi/cts/ScanResultTest.java
+++ b/tests/cts/net/src/android/net/wifi/cts/ScanResultTest.java
@@ -227,7 +227,14 @@
         }
         assertNotNull("Current network not found in scan results", currentNetwork);
 
-        assertEquals(wifiInfo.getWifiSsid(), currentNetwork.wifiSsid);
+        String wifiInfoSsidQuoted = wifiInfo.getSSID();
+        String scanResultSsidUnquoted = currentNetwork.SSID;
+
+        assertEquals(
+                "SSID mismatch: make sure this isn't a hidden network or an SSID containing "
+                        + "non-UTF-8 characters - neither is supported by this CTS test.",
+                wifiInfoSsidQuoted,
+                "\"" + scanResultSsidUnquoted + "\"");
         assertEquals(wifiInfo.getFrequency(), currentNetwork.frequency);
     }
 }