Update ThreadSafeDataBuffer to use `std::span<const uint8_t>` instead of `const void*`.
Pull request: https://github.com/WebKit/WebKit/pull/29083
Committed 279298@main (60717e784729): <https://commits.webkit.org/279298@main> Reviewed commits have been landed. Closing PR #29083 and removing active labels.
<rdar://problem/128708794>