Feat: Fixed the issue that the top toolbar disappears when opening the agent operator form #3221 (#8579)

### What problem does this PR solve?

Feat: Fixed the issue that the top toolbar disappears when opening the
agent operator form #3221

### Type of change


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

web/src/pages/agent/canvas/index.less

@@ -1,6 +1,6 @@
 .canvasWrapper {
   position: relative;
-  height: 100%;
+  height: calc(100% - 64px);
   :global(.react-flow__node-group) {
     .commonNode();
     border-radius: 0 0 10px 10px;

web/src/pages/agent/canvas/index.tsx

@@ -174,6 +174,7 @@ function AgentCanvas({ drawerVisible, hideDrawer }: IProps) {
           isValidConnection={isValidConnection}
           onEdgeMouseEnter={onEdgeMouseEnter}
           onEdgeMouseLeave={onEdgeMouseLeave}
+          className="h-full"
           defaultEdgeOptions={{
             type: 'buttonEdge',
             markerEnd: 'logo',