Remove pointless checks

Signed-off-by: Alex Saveau <[email protected]>

Author: SUPERCILEX

auth/src/main/java/com/firebase/ui/auth/AuthUI.java

@@ -282,9 +282,6 @@ public Task<AuthResult> silentSignIn(@NonNull Context context,
         if (mAuth.getCurrentUser() != null) {
             throw new IllegalArgumentException("User already signed in!");
         }
-        if (desiredConfigs.isEmpty()) {
-            throw new IllegalArgumentException("At least one provider must be specified.");
-        }
 
         List<IdpConfig> configs = new ArrayList<>();
         for (IdpConfig config : desiredConfigs) {
@@ -296,7 +293,8 @@ public Task<AuthResult> silentSignIn(@NonNull Context context,
         }
 
         if (configs.isEmpty()) {
-            throw new IllegalArgumentException("No supported providers were supplied.");
+            throw new IllegalArgumentException("No supported providers were supplied. " +
+                    "Add either Google or email support.");
         }
 
         final Context appContext = context.getApplicationContext();