The test_check_dependencies_missing_appindicator test was failing because
it expected check_dependencies() to return False when AppIndicator3 is
missing. However, the code now supports AyatanaAppIndicator3 as a fallback.
Split the test into two cases:
- test_check_dependencies_missing_appindicator_with_ayatana_fallback:
Tests that when AppIndicator3 is missing but AyatanaAppIndicator3
is available, check_dependencies() returns True (fallback works)
- test_check_dependencies_missing_both_appindicators:
Tests that when both AppIndicator3 and AyatanaAppIndicator3 are
missing, check_dependencies() returns False