RFR: 8359445: GHA: Update gradle wrapper-validation action to v4

[Kevin Rushforth]

As noted in JBS, our GitHub Actions workflow uses `gradle/actions/wrapper-validation at v3`. We should update to the latest version, which is v4.

In addition to it being a good idea to use the latest, we've seen a lot of intermittent failures in gradle validation, and I hope this might help.

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Commit messages:
 - GHA: Update gradle wrapper-validation to v4

Changes: https://git.openjdk.org/jfx/pull/1826/files
  Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1826&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8359445
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jfx/pull/1826.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1826/head:pull/1826

PR: https://git.openjdk.org/jfx/pull/1826