fix(stores): Stores fixes and testing (#4663)

* fix(stores): Actually check a vector is a unit vector/normalized

Instead of just summing the components to see if they equal 1.0, take
the actual magnitude/p-norm of the vector and check that is
approximately 1.0.

Note that this shouldn't change the order of results except in edge
cases if I am too lax with the precision of the equality
comparison. However it should improve performance for normalized
vectors which were being misclassified.

Signed-off-by: Richard Palethorpe <io@richiejp.com>

* fix(stores): Add tests for known results and triangle inequality

This adds some more tests to check the cosine similarity function has
some expected mathematical properties.

Signed-off-by: Richard Palethorpe <io@richiejp.com>

---------

Signed-off-by: Richard Palethorpe <io@richiejp.com>