Feat: Replace color variables according to design draft #3221 (#9305)

### What problem does this PR solve?

Feat: Replace color variables according to design draft #3221

### Type of change


- [x] New Feature (non-breaking change which adds functionality)

web/src/pages/agent/canvas/node/agent-node.tsx

@@ -89,7 +89,7 @@ function InnerAgentNode({
           {(isGotoMethod ||
             exceptionMethod === AgentExceptionMethod.Comment) && (
             <div className="bg-bg-card rounded-sm p-1 flex justify-between gap-2">
-              <span className="text-text-sub-title">On Failure</span>
+              <span className="text-text-secondary">On Failure</span>
               <span className="truncate flex-1 text-right">
                 {t(`flow.${exceptionMethod}`)}
               </span>
@@ -101,7 +101,7 @@ function InnerAgentNode({
             type="source"
             position={Position.Right}
             isConnectable={isConnectable}
-            className="!bg-text-delete-red"
+            className="!bg-state-error"
             style={{ ...RightHandleStyle, top: 94 }}
             nodeId={id}
             id={NodeHandleId.AgentException}