views: Remove GetHeightForWidth in //ash/login.

Because both GetHeightForWidth and CalculatePreferredSize can provide
calculation options for preferred size calculation, but in some cases we
have to calculate both. Their coexistence also leads to some
implementation differences. In fact, we can merge them through
CalculatePreferredSize(views::SizeBounds).

Now is the stage to delete the GetHeightForWidth overload.

Bug: 40232718
Change-Id: I18b9cb37d522561a06f9bce553e9de30750243a4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5741321
Reviewed-by: Denis Kuznetsov <antrim@chromium.org>
Commit-Queue: Weidong Liu <weidongliu@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1339729}