[Build Break] Update custom serialization min supported version (#3458)

Update custom serialization min supported version, should be 2.11.0
since the features backport [1] was merged.

- [1] #3444 

Signed-off-by: Peter Nied <petern@amazon.com>

src/main/java/org/opensearch/security/support/ConfigConstants.java

@@ -326,7 +326,7 @@ public enum RolesMappingResolution {
     public static final String TENANCY_GLOBAL_TENANT_DEFAULT_NAME = "";
 
     public static final String USE_JDK_SERIALIZATION = "plugins.security.use_jdk_serialization";
-    public static final Version FIRST_CUSTOM_SERIALIZATION_SUPPORTED_OS_VERSION = Version.V_3_0_0;
+    public static final Version FIRST_CUSTOM_SERIALIZATION_SUPPORTED_OS_VERSION = Version.V_2_11_0;
 
     // On-behalf-of endpoints settings
     // CS-SUPPRESS-SINGLE: RegexpSingleline get Extensions Settings

src/test/java/org/opensearch/security/transport/SecuritySSLRequestHandlerTests.java

@@ -66,12 +66,17 @@ public void testUseJDKSerializationHeaderIsSetOnMessageReceived() throws Excepti
         TransportChannel transportChannel = mock(TransportChannel.class);
         Task task = mock(Task.class);
         doNothing().when(transportChannel).sendResponse(ArgumentMatchers.any(Exception.class));
-        when(transportChannel.getVersion()).thenReturn(Version.V_2_11_0);
+        when(transportChannel.getVersion()).thenReturn(Version.V_2_10_0);
         when(transportChannel.getChannelType()).thenReturn("transport");
 
         Assert.assertThrows(Exception.class, () -> securitySSLRequestHandler.messageReceived(transportRequest, transportChannel, task));
         Assert.assertTrue(threadPool.getThreadContext().getTransient(ConfigConstants.USE_JDK_SERIALIZATION));
 
+        threadPool.getThreadContext().stashContext();
+        when(transportChannel.getVersion()).thenReturn(Version.V_2_11_0);
+        Assert.assertThrows(Exception.class, () -> securitySSLRequestHandler.messageReceived(transportRequest, transportChannel, task));
+        Assert.assertFalse(threadPool.getThreadContext().getTransient(ConfigConstants.USE_JDK_SERIALIZATION));
+
         threadPool.getThreadContext().stashContext();
         when(transportChannel.getVersion()).thenReturn(Version.V_3_0_0);
         Assert.assertThrows(Exception.class, () -> securitySSLRequestHandler.messageReceived(transportRequest, transportChannel, task));