tdbPartitionedMatrix will automatically close Array's when done reading

[jparismorgan]

What

Today tdbPartitionedMatrix will leave std::unique_ptr<tiledb::Array> partitioned_vectors_array_ and std::unique_ptr<tiledb::Array> partitioned_ids_array_ open until the destructor. This was causing issues in #447 because we have a static function on our indexes which will try to call tiledb::Array::delete_fragments() on these Array's, but that will throw if the Array's are already open somewhere, which they are in tdbPartitionedMatrix.

Testing

• Existing unit tests pass.
• Undos changes to Python which were added in Support IVF PQ consolidation by storing raw feature vectors and external IDs #447 to work around this issue.
• Adds new clear history with an open index unit tests to Vamana and IVFPQ which make sure you can query and then call clear_history(). Note that Vamana doesn't need the changes in this PR to pass that tests, but IVFPQ fails without it.
• Adds checks for tdb_partioned_matrix.load() = false in several places that didn't have it.

[NikolaosPapailiou]

Thanks for fixing this!