Revert "Include missing lines in coverage report"

Too many lines missing ^^

This reverts commit 6b39784a.

tools/tests/test-pytest.sh

@@ -3,4 +3,4 @@
 # SPDX-License-Identifier: AGPL-3.0-only
 # License-Filename: LICENSE.md
 
-PYTHONPATH=briar-gtk/briar_gtk pytest --cov-report term-missing --cov=briar_gtk briar-gtk/tests/
+PYTHONPATH=briar-gtk/briar_gtk pytest --cov=briar_gtk briar-gtk/tests/