fix(gen-ai): Re-query server row after modal close to avoid stale reference

After saving tool selection and closing the modal in the auto-unlock
test, re-query the server row before clicking the tools button again.
This prevents stale element references that can cause flaky test
failures when the DOM updates after modal interactions.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: toklumpp

packages/gen-ai/frontend/src/__tests__/cypress/cypress/tests/mocked/playground/mcpTab.cy.ts

@@ -424,7 +424,9 @@ describe('Playground - MCP Servers', () => {
           mcpToolsModal.find().should('not.exist');
 
           cy.step('Re-open tools modal to verify persistence');
-          freshServerRow.findToolsButton().click();
+          // Re-query server row after modal closes to avoid stale reference
+          const reopenServerRow = playgroundPage.mcpTab.getServerRow(serverName, serverUrl);
+          reopenServerRow.findToolsButton().click();
           mcpToolsModal.find().should('be.visible');
 
           cy.step('Verify tool selection persisted (2 tools deselected)');