[jdk24u] RFR: 8348598: Update Libpng to 1.6.47

[duke]

On Wed, 19 Mar 2025 16:37:16 GMT, Harshitha Onkar <honkar at openjdk.org> wrote:

> Hi all,
> 
> This pull request contains a backport of commit [6b82b42a](https://github.com/openjdk/jdk/commit/6b82b42a2116900b2125e03c1ffa0824d6062757) from the [openjdk/jdk](https://git.openjdk.org/jdk) repository.
> 
> The commit being backported was authored by Harshitha Onkar on 17 Mar 2025 and was reviewed by Alexander Zvegintsev, Phil Race and Erik Joelsson.
> 
> Thanks!

@honkar-jdk 
Your change (at version 2627d6c097e7be80b589d3b7d7371c28d1a71a93) is now ready to be sponsored by a Committer.

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PR Comment: https://git.openjdk.org/jdk24u/pull/149#issuecomment-2744346597