fix(linux): apt_update_upgrade left dependency-driven updates pending

Plain "apt-get upgrade" refuses to install or remove packages even when
a newer version requires it, silently holding those updates back —
switched to "apt-get full-upgrade" so VM-provisioning bootstrap actually
finishes with nothing left to update.

tests/test_linux.py

@@ -776,7 +776,9 @@ class TestActionAptUpdateUpgrade:
         assert "[upgrade]" in result["output"]
         update_call, upgrade_call = mock_sudo.call_args_list
         assert "apt-get update" in update_call.args[0]
-        assert "apt-get upgrade" in upgrade_call.args[0]
+        # full-upgrade (not plain upgrade) — plain upgrade silently holds back
+        # packages whose newer version needs to install/remove dependencies.
+        assert "apt-get full-upgrade" in upgrade_call.args[0]
 
     def test_exception_during_upgrade_returns_failure(self, driver):
         driver._pkg_manager = "apt"