set Timezone Europe/Berlin in unit tests (#3087)

needed for new formatTime unit tests.

Avoiding ugly TZ setting in github workflows, see
https://github.com/MichMich/MagicMirror/pull/3073

.github/workflows/automated-tests.yaml

@@ -22,12 +22,6 @@ jobs:
     steps:
       - name: "Checkout code"
         uses: actions/checkout@v3
-      - name: "Set timezone"
-        uses: szenius/set-timezone@v1.2
-        with:
-          timezoneLinux: "Europe/Berlin"
-          timezoneMacos: "Europe/Berlin"
-          timezoneWindows: "Europe/Berlin"
       - name: "Use Node.js ${{ matrix.node-version }}"
         uses: actions/setup-node@v3
         with:

.github/workflows/codecov-test-suites.yaml

@@ -19,12 +19,6 @@ jobs:
     steps:
       - name: "Checkout code"
         uses: actions/checkout@v3
-      - name: "Set timezone"
-        uses: szenius/set-timezone@v1.2
-        with:
-          timezoneLinux: "Europe/Berlin"
-          timezoneMacos: "Europe/Berlin"
-          timezoneWindows: "Europe/Berlin"
       - name: "Install dependencies and run coverage"
         run: |
           Xvfb :99 -screen 0 1024x768x16 &