Fix check workflow failure in Gradle wrapper validation

[Copilot]

The check workflow was failing before any Gradle tasks ran because the wrapper validation step used an obsolete action. This updates the workflow to the maintained Gradle wrapper validation action and refreshes the checkout action pin used by the same job.

• Workflow fix

  • Replace gradle/wrapper-validation-action with gradle/actions/wrapper-validation
  • Keep the step behavior the same while moving to the supported action lineage

• Action pin refresh

  • Update actions/checkout to a current pinned SHA
  • Removes reliance on the older checkout release used by the failing job

• Net effect

  • The check job can proceed past wrapper validation instead of failing at step 4
  • Checkstyle, PMD, and tests are no longer blocked by the workflow action failure

- uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2

- name: Validate Gradle wrapper
  uses: gradle/actions/wrapper-validation@50e97c2cd7a37755bbfafc9c5b7cafaece252f6e # v6.1.0