[-Wunsafe-buffer-usage] Warning for unsafe invocation of span::data (#75650)

…-Wunsafe-buffer-usage,

there maybe accidental re-introduction of new OutOfBound accesses into
the code bases. One such case is invoking span::data() method on a span
variable to retrieve a pointer, which is then cast to a larger type and
dereferenced. Such dereferences can introduce OutOfBound accesses.

To address this, a new WarningGadget is being introduced to warn against
such invocations.

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Co-authored-by: MalavikaSamak <malavika2@apple.com>