Websocket APIs cannot be invoked due to NPE.
### Description:

Websocket APIs cannot be invoked due to NPE in enforcer. 

### Steps to reproduce:
start choreo-connect-with-apim
Deploy websocketAPI 
Invoke the API with a valid token obtained from devportal

### Affected Product Version:
choreo-connect-1.0.0-beta2-snapshot

### Environment details (with versions):
- OS:
- Client:
- Env (Docker/K8s):

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diff --git a/enforcer-parent/enforcer/src/main/java/org/wso2/choreo/connect/enforcer/security/AuthFilter.java b/enforcer-parent/enforcer/src/main/java/org/wso2/choreo/connect/enforcer/security/AuthFilter.java
index a93a71489..fbe71d153 100644
--- a/enforcer-parent/enforcer/src/main/java/org/wso2/choreo/connect/enforcer/security/AuthFilter.java
+++ b/enforcer-parent/enforcer/src/main/java/org/wso2/choreo/connect/enforcer/security/AuthFilter.java
@@ -234,7 +234,10 @@ public class AuthFilter implements Filter {
         }
 
         ResourceConfig resourceConfig = requestContext.getMatchedResourcePath();
-        if (resourceConfig.getEndpoints().containsKey(keyType)) {
+        // In websockets case, the endpoints object becomes null. Hence it would result
+        // in a NPE, if it is not checked.
+        if (resourceConfig.getEndpoints() != null &&
+                resourceConfig.getEndpoints().containsKey(keyType)) {
             EndpointCluster endpointCluster = resourceConfig.getEndpoints().get(keyType);
 
             // Apply resource level retry headers
['enforcer-parent/enforcer/src/main/java/org/wso2/choreo/connect/enforcer/security/AuthFilter.java']