webkitgtk: fix CVE-2022-46700

A memory corruption issue was addressed with improved input validation.
This issue is fixed in Safari 16.2, tvOS 16.2, macOS Ventura 13.1, iOS
15.7.2 and iPadOS 15.7.2, iOS 16.2 and iPadOS 16.2, watchOS 9.2. Processing
maliciously crafted web content may lead to arbitrary code execution.

References:
https://support.apple.com/en-us/HT213531
https://bugs.webkit.org/show_bug.cgi?id=247562
https://github.com/WebKit/WebKit/pull/6266



Signed-off-by: Yogita Urade <yogita.urade@windriver.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>