ci: Collapse deploy-snapshot JDK setup into the jdk-setup action

The jdk-setup composite action now accepts Maven Central credentials, so
deploy-snapshot no longer needs a separate setup-java step after it. Pass
the server inputs to jdk-setup and drop the redundant second JDK setup.
Behavior is unchanged — snapshots are unsigned, so no GPG inputs are
needed, and the action still configures JDK 21 with Maven caching.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DGSbyBPTxsj73xhYpnxcse

Author: jeffjensen

.github/workflows/deploy-snapshot.yml

@@ -18,10 +18,7 @@ jobs:
     steps:
       - uses: actions/checkout@v7
       - uses: ./.github/actions/jdk-setup
-      - uses: actions/setup-java@v5
         with:
-          java-version: '21'
-          distribution: 'temurin'
           server-id: central-publish
           server-username: CENTRAL_USERNAME
           server-password: CENTRAL_TOKEN