Bump actions/download-artifact from 5 to 6

Bumps [actions/download-artifact](https://github.com/actions/download-artifact) from 5 to 6.
- [Release notes](https://github.com/actions/download-artifact/releases)
- [Commits](actions/download-artifact@v5...v6)

---
updated-dependencies:
- dependency-name: actions/download-artifact
  dependency-version: '6'
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

.github/workflows/deploy_beta_testing.yml

@@ -50,7 +50,7 @@ jobs:
       - uses: actions/checkout@v5
 
       - name: Download war artifact
-        uses: actions/download-artifact@v5
+        uses: actions/download-artifact@v6
         with:
           name: built-app
           path: ./

.github/workflows/maven_unit_test.yml

@@ -112,7 +112,7 @@ jobs:
                   cache: maven
 
             # Get the build output from the unit test job
-            - uses: actions/download-artifact@v5
+            - uses: actions/download-artifact@v6
               with:
                   name: java-artifacts
             - run: |
@@ -145,7 +145,7 @@ jobs:
                 cache: maven
 
           # Get the build output from the integration test job
-          - uses: actions/download-artifact@v5
+          - uses: actions/download-artifact@v6
             with:
                 name: java-reportdir
           - run: tar -xvf java-reportdir.tar