fix(test): pass --ignore-engines to yarn in sandbox specs

`b4912ad7eb` removed the repo-root `.yarnrc` (`ignore-engines true`).
`openfeature.spec.js` still shells out to yarn after `bun add` pulls in
`@hono/node-server@2.x` (`engines.node >= 20`), so on the node-oldest
matrix entry yarn errors before the build step and the integration-esbuild
job hangs past 30 minutes against ~160s on master.

`iast-stack-traces-with-sourcemaps` follows the same shape with deps that
happen to be Node-18-clean today; pass the flag inline there too to keep
the contract explicit so a future dep bump can't silently break the same
matrix entry again.

Author: BridgeAR

integration-tests/appsec/iast-stack-traces-with-sourcemaps.spec.js

@@ -17,7 +17,11 @@ describe('IAST stack traces and vulnerabilities with sourcemaps', () => {
 
     appDir = path.join(cwd, 'appsec', 'iast-stack-traces-ts-with-sourcemaps')
 
-    childProcess.execSync('yarn || yarn', { cwd })
+    // The root `.yarnrc` that used to carry `ignore-engines true` is gone. The current
+    // sandbox deps happen to be clean on every supported Node version, so pass the flag
+    // inline to keep the contract explicit and stop a future dep bump from silently
+    // breaking the node-oldest matrix. Keep the retry pattern for transient registry blips.
+    childProcess.execSync('yarn --ignore-engines || yarn --ignore-engines', { cwd })
     childProcess.execSync('npx tsc', {
       cwd: appDir,
     })

integration-tests/esbuild/openfeature.spec.js

@@ -23,7 +23,10 @@ esbuildVersions.forEach((version) => {
       execSync(`rm -rf ${path.join(cwd, 'bun.lock')}`, { cwd })
       execSync('npm install -g yarn', { cwd })
 
-      execSync('yarn', { cwd })
+      // `@hono/node-server@2.x` declares `engines.node >= 20`. The matrix still exercises
+      // node-oldest (18), and the root `.yarnrc` that used to carry `ignore-engines true`
+      // is gone, so yarn would error out before we ever build. Pass the flag inline.
+      execSync('yarn --ignore-engines', { cwd })
     })
 
     beforeEach(async () => {