[js][bidi] Fix network inspector test

Refer: https://github.com/web-platform-tests/wpt/blob/c71b71b002b58c722e82767e12107862793eaed0/webdriver/tests/bidi/network/before_request_sent/before_request_sent.py#L231 for expected cookie format

javascript/node/selenium-webdriver/test/bidi/bidi_test.js

@@ -1802,7 +1802,7 @@ suite(
 
         assert.equal(beforeRequestEvent.request.method, 'GET')
         assert.equal(beforeRequestEvent.request.cookies[0].name, 'north')
-        assert.equal(beforeRequestEvent.request.cookies[0].value, 'biryani')
+        assert.equal(beforeRequestEvent.request.cookies[0].value.value, 'biryani')
         const url = beforeRequestEvent.request.url
         assert.equal(url, await driver.getCurrentUrl())
 
@@ -1813,7 +1813,7 @@ suite(
         await driver.navigate().refresh()
 
         assert.equal(beforeRequestEvent.request.cookies[1].name, 'south')
-        assert.equal(beforeRequestEvent.request.cookies[1].value, 'dosa')
+        assert.equal(beforeRequestEvent.request.cookies[1].value.value, 'dosa')
       })
 
       it('can redirect http equiv', async function () {