fix: catch RuntimeError for missing torch import

chore: update pyproject

chore: fix numerical inconsistencies

test: add tests for tokenizers

chore: fit sparse encoders after route modifications in HybridRouter

fix: remove decorator around the HybridRouter.__init__

fix: give the functional BM25 a distinct filename

fix: fix route fitting for add/strategy

fix: _async_encode should take a sparse encoding function

fix: empty sparse embeddings

fix: _encode / _async_encode match superclass signature

* Enable to set top_k for RouteLayer

* Add top_k unit test for RouteLayer

* Added support for setting different aggregation method for HybridRL

* Add unit test to verify that aggregation works

* Add support for setting aggregation in RouteLayer

* Fix bug where agg method not used in RL

* Add tests for agg

* Linted code

* Updated codecov file

* Change aggregation method names to lower case

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Co-authored-by: James Briggs <35938317+jamescalam@users.noreply.github.com>