Fix environment variable check to skip tests when either variable is missing

- Changed logic from AND to OR: skip test if endpoint OR key is missing
- Both environment variables are required for integration tests to run
- This ensures tests are skipped in Azure DevOps pipeline without proper credentials

Author: Changjian Wang

sdk/contentunderstanding/azure-ai-contentunderstanding/src/test/java/com/azure/ai/contentunderstanding/generated/ContentUnderstandingClientTestBase.java

@@ -27,12 +27,16 @@ class ContentUnderstandingClientTestBase extends TestProxyTestBase {
      * Utility method to check if required environment variables are available.
      * If they are not available, the test will be skipped.
      * This is useful for integration tests that require real Azure credentials.
+     * 
+     * Both CONTENTUNDERSTANDING_ENDPOINT and AZURE_CONTENT_UNDERSTANDING_KEY must be set
+     * for the test to run. If either is missing, the test is skipped.
      */
     protected static void skipIfRequiredEnvironmentVariablesNotSet() {
         String endpoint = Configuration.getGlobalConfiguration().get("CONTENTUNDERSTANDING_ENDPOINT");
         String key = System.getenv("AZURE_CONTENT_UNDERSTANDING_KEY");
 
-        if ((endpoint == null || endpoint.trim().isEmpty()) && (key == null || key.trim().isEmpty())) {
+        // Skip test if either required environment variable is missing or empty
+        if ((endpoint == null || endpoint.trim().isEmpty()) || (key == null || key.trim().isEmpty())) {
             throw new TestAbortedException(
                 "Required environment variables CONTENTUNDERSTANDING_ENDPOINT or AZURE_CONTENT_UNDERSTANDING_KEY are not set. Skipping test.");
         }