Measure test coverage of exceptions (#7823)

Part of #6528.

IMO, exceptions are also part of the public API so we should measure the
test coverage over them, but feel free to close this PR if you think
otherwise ;)

---------

Co-authored-by: rusty1s <matthias.fey@tu-dortmund.de>

pyproject.toml

@@ -161,8 +161,7 @@ omit = [
 exclude_lines = [
     "pragma: no cover",
     "pass",
-    "raise",
-    "except",
+    "raise NotImplementedError",
     "register_parameter",
     "warn",
     "torch.cuda.is_available",