ci: install toposort/igraph before the ifcpatch test step

test_Optimise.py (added in 57cfd9d1fd) exercises the Optimise recipe's
patch(), which since 7ebdd046b6 hard-requires the `toposort` package
as its fallback path (igraph is optional and its tests properly
pytest.importorskip when absent). ci.yml never installed either, so
every `cd ../ifcpatch && make test` run since 07-18 has been failing
with ModuleNotFoundError, contributing to the same "Test
ifcopenshell-python" step failure alongside the validate_stub crash
fixed in the previous commit.

Verified locally: test/test_Optimise.py's 6 tests (both the igraph and
pure-python toposort fallback paths) fail with ModuleNotFoundError
without these packages installed, and pass with them installed.

Generated with the assistance of an AI coding tool.

.github/workflows/ci.yml

@@ -255,6 +255,7 @@ jobs:
           cd ../bsdd && make test || ERROR=1
           pip install deepdiff
           cd ../ifcdiff && make test || ERROR=1
+          pip install toposort igraph
           cd ../ifcpatch && make test || ERROR=1
           pip install -e ../ifc5d --no-deps
           pip install odfpy xlsxwriter