Fix crash on potentially missing EuiccManager

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

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();