Fix crash when retrieving mock configuration on iOS.

If configuration wasn't set for a mock / fake class, ConfigGet() would
previously crash. This change modifies the method to optionally retrieve
configuration from the FlatBuffer.

PiperOrigin-RevId: 264635894

Author: smiles

testing/config_ios.mm

@@ -35,9 +35,11 @@ void ConfigSet(const char* test_data_in_json) {
   const TestDataConfig* config = GetTestDataConfig(g_test_data_config);
   // LookupByKey() does not work because the data passed in may not conform. So
   // we just iterate over the test data.
-  for (const ConfigRow* row : *(config->config())) {
-    if (strcmp(row->fake()->c_str(), fake) == 0) {
-      return row;
+  if (config->config()) {
+    for (const ConfigRow* row : *(config->config())) {
+      if (row->fake() && strcmp(row->fake()->c_str(), fake) == 0) {
+        return row;
+      }
     }
   }
   return nullptr;