Otter-grader

* Fixed the no PDF acknowledgement feature to handle when PDF exports throw an error instead of failing silently

* Fixed an `AttributeError` when using `Notebook.check_all` per [746](https://github.com/ucbds-infra/otter-grader/issues/746)

* Fixed an `AttributeError` when using OK tests from notebook metadata per [743](https://github.com/ucbds-infra/otter-grader/issues/743)

* Migrate installation of `ottr` from `setup.sh` to `environment.yml` with the [`r-ottr` conda-forge recipe](https://anaconda.org/conda-forge/r-ottr)
* Updated Otter Assign to allow multiline statements in test cases for Python 3.9+ per [590](https://github.com/ucbds-infra/otter-grader/issues/590)
* Added `otter_include` tag to allow inclusion of tagged markdown cells within the solution block into the student notebook per [730](https://github.com/ucbds-infra/otter-grader/issues/730)
* Removed dependency on `nbconvert` during import so that Otter can be imported on Jupyterlite per [736](https://github.com/ucbds-infra/otter-grader/issues/736)

* Prevented the `Notebook` class from attempting to resolve the notebook path when in grading mode
* Gracefully handle a failure in reading the results pickle file by returning results indicating that such a failure has occurred per [723](https://github.com/ucbds-infra/otter-grader/issues/723)
* Use `tempfile.mkstemp` instead of `tempfile.NamedTemporaryFile` for the results pickle file used during notebook execution per [723issuecomment-1710689536](https://github.com/ucbds-infra/otter-grader/issues/723#issuecomment-1710689536)

* Fixed bug in submission zip download link per [719](https://github.com/ucbds-infra/otter-grader/issues/719)