Revert "Reland "Add check for valid URL in `ui::DataTransferEndpoint` constructor""

This reverts commit 158a44415a275f0a0df48adc75d4e80266eb5989.

Reason for revert: crbug.com/347861872

Original change's description:
> Reland "Add check for valid URL in `ui::DataTransferEndpoint` constructor"
>
> This is a reland of commit 607d686c0adcd7a8e57baf88a6c320df9d950eba
>
> The failing test is reproducible locally and is fixed by the code
> added in content/browser/web_contents/web_contents_view_aura.cc
>
> Original change's description:
> > Add check for valid URL in `ui::DataTransferEndpoint` constructor
> >
> > Follow-up to the comments in crrev.com/c/5598457/8
> >
> > This CL adds a CHECK so that a `EndpointType::kUrl` DTE is always
> > initialized with a valid GURL by caller code. Following the same logic,
> > this CL also switches the other constructor from using
> > `DCHECK_NE(type, EndpointType::kUrl);` to using `CHECK_NE`.
> >
> > Change-Id: I0edc94fd5f92e9ce557dd316882174a991d78dd0
> > Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5610267
> > Reviewed-by: Daniel Cheng <dcheng@chromium.org>
> > Reviewed-by: Sergey Poromov <poromov@chromium.org>
> > Auto-Submit: Dominique Fauteux-Chapleau <domfc@chromium.org>
> > Commit-Queue: Avi Drissman <avi@chromium.org>
> > Reviewed-by: Avi Drissman <avi@chromium.org>
> > Cr-Commit-Position: refs/heads/main@{#1314649}
>
> Change-Id: I6a2f6fe9bd11b0b5cd6de97c0da2a0b5aafbe380
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5630262
> Auto-Submit: Dominique Fauteux-Chapleau <domfc@chromium.org>
> Commit-Queue: Sergey Poromov <poromov@chromium.org>
> Reviewed-by: Avi Drissman <avi@chromium.org>
> Reviewed-by: Sergey Poromov <poromov@chromium.org>
> Cr-Commit-Position: refs/heads/main@{#1315714}

Bug: 347861872
Change-Id: Id59fd57a7394a1decc39fd7a916901e242f4a115
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5648178
Reviewed-by: Avi Drissman <avi@chromium.org>
Reviewed-by: Sergey Poromov <poromov@chromium.org>
Commit-Queue: Avi Drissman <avi@chromium.org>
Auto-Submit: Dominique Fauteux-Chapleau <domfc@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1317954}