tests: Fix issue where gettext is not individually installed in some modules.

.github/workflows/build.yml

@@ -17,7 +17,7 @@ jobs:
     steps:
       - uses: actions/checkout@v3
       - name: Set up Python
-        uses: actions/setup-python@v4
+        uses: actions/setup-python@v5
         with:
           python-version: '3.8'
       - name: Display Python info

.github/workflows/test.yml

@@ -25,7 +25,7 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - name: Set up Python
-        uses: actions/setup-python@v4
+        uses: actions/setup-python@v5
         with:
           python-version: ${{ matrix.python-version }}
       - name: Display Python info

tests/interface/test_dialogs.py

@@ -5,6 +5,7 @@
 import os
 
 import pytest
+import mu.i18n
 import mu.interface.dialogs
 from PyQt5.QtWidgets import QDialog, QWidget, QDialogButtonBox
 from unittest import mock

tests/interface/test_editor.py

@@ -3,6 +3,7 @@
 Tests for the user interface elements of Mu.
 """
 from unittest import mock
+import mu.i18n
 import mu.interface.editor
 import keyword
 import re