set java version to fix emulator tools

Author: lahirumaramba

.github/workflows/ci.yml

@@ -37,6 +37,12 @@ jobs:
       uses: actions/setup-node@v4
       with:
         node-version: 20
+    - name: Set up Java 21
+      uses: actions/setup-java@v5
+      with:
+        distribution: 'temurin'
+        java-version: '21'
+        check-latest: true
     - name: Install firebase-tools
       run: npm install -g firebase-tools
     - name: Run Database emulator tests