Cleanup warnings and turn warnings into errors

[rsyring]

.nox/pytest-3-11-db-sqlite/lib/python3.11/site-packages/webob/compat.py:5
  /home/rsyring/projects/webgrid-src/.nox/pytest-3-11-db-sqlite/lib/python3.11/site-packages/webob/compat.py:5: DeprecationWarning: 'cgi' is deprecated and slated for removal in Python 3.13
    from cgi import parse_header

projects/webgrid-src/tests/webgrid_tests/test_testing.py::TestGridBase::test_filters
  /home/rsyring/projects/webgrid-src/tests/webgrid_ta/model/helpers.py:136: SAWarning: Identity map already had an identity for (<class 'webgrid_ta.model.entities.Person'>, (1,), None), replacing it with newly flushed object.   Are there load operations occurring inside of an event handler within the flush?
    dbsess.commit()

projects/webgrid-src/tests/webgrid_tests/test_unit.py::TestGrid::test_static_path
  /home/rsyring/projects/webgrid-src/tests/webgrid_ta/model/helpers.py:136: SAWarning: Identity map already had an identity for (<class 'webgrid_ta.model.entities.Person'>, (2,), None), replacing it with newly flushed object.   Are there load operations occurring inside of an event handler within the flush?
    dbsess.commit()

projects/webgrid-src/tests/webgrid_tests/test_unit.py::TestGrid::test_static_path
  /home/rsyring/projects/webgrid-src/tests/webgrid_ta/model/helpers.py:136: SAWarning: Identity map already had an identity for (<class 'webgrid_ta.model.entities.Person'>, (3,), None), replacing it with newly flushed object.   Are there load operations occurring inside of an event handler within the flush?
    dbsess.commit()

projects/webgrid-src/tests/webgrid_tests/test_unit.py::TestGrid::test_static_path
  /home/rsyring/projects/webgrid-src/tests/webgrid_ta/model/helpers.py:136: SAWarning: Identity map already had an identity for (<class 'webgrid_ta.model.entities.Person'>, (4,), None), replacing it with newly flushed object.   Are there load operations occurring inside of an event handler within the flush?
    dbsess.commit()

Warning should already be errors since this is a coppy project. Related: level12/coppy#65