refactor(cache): remove unused method and fix misleading test name

Remove unused public getValidRegionNames() from CacheMaintenanceHelper —
dead code with no callers. Rename test to match what it actually verifies.

Author: hassandotcms

dotCMS/src/main/java/com/dotcms/rest/api/v1/system/cache/CacheMaintenanceHelper.java

@@ -11,8 +11,6 @@
 
 import com.dotcms.rest.exception.BadRequestException;
 import javax.enterprise.context.ApplicationScoped;
-import java.util.Set;
-import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 /**
@@ -71,17 +69,6 @@ public void flushAllCaches() {
         reloadPublishingFilters();
     }
 
-    /**
-     * Returns the set of valid cache region names derived from {@code CacheLocator.getCacheIndexes()}.
-     */
-    public Set<String> getValidRegionNames() {
-
-        final Object[] caches = CacheLocator.getCacheIndexes();
-        return Stream.of(caches)
-                .map(Object::toString)
-                .collect(Collectors.toSet());
-    }
-
     private boolean isValidRegion(final String regionName) {
 
         final Object[] caches = CacheLocator.getCacheIndexes();

dotcms-integration/src/test/java/com/dotcms/rest/api/v1/system/cache/CacheResourceIntegrationTest.java

@@ -223,10 +223,10 @@ public void test_flushRegion_unknown_returns_400() {
     /**
      * Given: Valid region name "System"
      * When: flushRegion is called
-     * Then: Flushes successfully (System triggers PushPublishing reload)
+     * Then: Flushes successfully (System region also triggers PushPublishing reload internally)
      */
     @Test
-    public void test_flushRegion_system_triggers_publishing_reload() {
+    public void test_flushRegion_system_returns_success() {
 
         final ResponseEntityStringView result =
                 cacheResource.flushRegion(