ci: Remove gradle-wrapper-validation job from GitHub Actions

See
https://github.com/gradle/actions?tab=readme-ov-file#the-wrapper-validation-action.

From setup-gradle@v4, it performs wrapper validation for every
execution, and the project doesn't need to run gradle-wrapper-validation
separately.

Signed-off-by: utzcoz <utzcoz@outlook.com>
Reviewed-by: Rylie Pavlik <rylie.pavlik@collabora.com>

Author: utzcoz

.github/workflows/gradle-wrapper-validation.yml

@@ -0,0 +1 @@
+ci: Remove now-redundant gradle-wrapper-validation job from GitHub Actions