Fix crash on potentially missing EuiccManager

Bug: 310710841
Test: it builds
Change-Id: I9d2c88091a34a4e4e118fd1bd8d95c724c52e77e

src/com/android/settings/MainClear.java

@@ -426,7 +426,7 @@ public class MainClear extends InstrumentedFragment implements OnGlobalLayoutLis
     @VisibleForTesting
     protected boolean isEuiccEnabled(Context context) {
         EuiccManager euiccManager = (EuiccManager) context.getSystemService(Context.EUICC_SERVICE);
-        return euiccManager.isEnabled();
+        return euiccManager != null && euiccManager.isEnabled();
     }
 
     @VisibleForTesting

src/com/android/settings/ResetNetwork.java

@@ -293,7 +293,7 @@ public class ResetNetwork extends InstrumentedFragment {
         }
         EuiccManager euiccManager =
                 (EuiccManager) context.getSystemService(Context.EUICC_SERVICE);
-        if (!euiccManager.isEnabled()) {
+        if (euiccManager == null || !euiccManager.isEnabled()) {
             return false;
         }
         ContentResolver resolver = context.getContentResolver();

src/com/android/settings/network/telephony/MobileNetworkUtils.java

@@ -308,7 +308,7 @@ public class MobileNetworkUtils {
     public static Boolean showEuiccSettingsDetecting(Context context) {
         final EuiccManager euiccManager =
                 (EuiccManager) context.getSystemService(EuiccManager.class);
-        if (!euiccManager.isEnabled()) {
+        if (euiccManager == null || !euiccManager.isEnabled()) {
             Log.w(TAG, "EuiccManager is not enabled.");
             return false;
         }