webnn: Destroy WebNNGraphBuilder connection from the WebNN service
Ensures that a bad message is reported if any message is received
on the WebNNGraphBuilder interface after CreateGraph()
Bug: 354724062
Change-Id: Iebbe72be8983437ee469aaa291fb6deb3b8cf43d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5741053
Reviewed-by: Alex Gough ajgo@chromium.org
Reviewed-by: Phillis Tang phillis@chromium.org
Commit-Queue: Austin Sullivan asully@chromium.org
Cr-Commit-Position: refs/heads/main@{#1334412}