[APC] Trigger request to MES if Enter click did not work

Adds the code to call the optimization service if the click with Enter didn't work. The service will return the dom node id of the button to click. Executing the button click will be implemented in the follow up.

Bug: 407487665
Change-Id: Ia3054af6ba87699c576842cfd63a061caaaf762e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6607358
Commit-Queue: Anna Tsvirchkova <atsvirchkova@google.com>
Reviewed-by: Vasilii Sukhanov <vasilii@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1469861}