Feature/fix headers filter

Description

Description of the MR

Merge Request Checklists

• I have already covered the unit testing
• Logical data model has been updated
• Deployment documentation has been updated

Optional Additional notes

src/main/java/com/aruba/simpl/tlsgateway/filters/HeadersFilter.java

@@ -40,23 +40,33 @@ public class HeadersFilter implements GlobalFilter, Ordered {
         log.info("Headers Filter...");
         var credentialId = ExchangeUtil.getCredentialIdFromExchange(serverWebExchange);
         return Mono.just(serverWebExchange).flatMap(exchange -> {
-            var jwt = getTierOneToken(exchange);
-            var epAttributes = getIdentityAttributeCodes(getEphemeralProofAttributes(exchange));
-            var endUserAttributes = jwt
-                    .map(token -> {
-                        validateSession(serverWebExchange, token, credentialId);
-                        return token;
-                    })
-                    .map(this::getIdentityAttributeCodes)
-                    .orElse(List.of())
-                    .stream();
-            var attributes = Stream.concat(epAttributes, endUserAttributes).toList();
-            exchange = addAbacAttributeToRequest(exchange, attributes);
-            exchange = addHeadersToRequest(exchange, credentialId);
+            var jwt = getValidJwtOrThrow(serverWebExchange, exchange, credentialId);
+            var attributes = getIdentityAttributes(exchange, jwt);
+            exchange = decorateRequest(exchange, attributes, credentialId);
             return chain.filter(exchange);
         });
     }
 
+    private ServerWebExchange decorateRequest(
+            ServerWebExchange exchange, List<String> attributes, String credentialId) {
+        exchange = addAbacAttributeToRequest(exchange, attributes);
+        exchange = addHeadersToRequest(exchange, credentialId);
+        return exchange;
+    }
+
+    private List<String> getIdentityAttributes(ServerWebExchange exchange, Optional<SignedJWT> jwt) {
+        var epAttributes = getIdentityAttributeCodes(getEphemeralProofAttributes(exchange));
+        var endUserAttributes = jwt.map(this::getIdentityAttributeCodes).orElse(List.of()).stream();
+        return Stream.concat(epAttributes, endUserAttributes).toList();
+    }
+
+    private Optional<SignedJWT> getValidJwtOrThrow(
+            ServerWebExchange serverWebExchange, ServerWebExchange exchange, String credentialId) {
+        var jwt = getTierOneToken(exchange);
+        jwt.ifPresent(signedJWT -> validateSession(serverWebExchange, signedJWT, credentialId));
+        return jwt;
+    }
+
     private ServerWebExchange addAbacAttributeToRequest(ServerWebExchange exchange, List<String> attributes) {
         if (!attributes.isEmpty()) {
             return exchange.mutate()