[BUG] cagra filter test returns duplicate neighbor indices

[mfoerste4]

Describe the bug
A new consistency check added in #2221 caused some cagra filter tests to fail. The resulting neighborhood does seem to contain duplicate neighboring ids. The effect is not limited to the #2221 branch but could also be reproduced without the changes to the IVF-flat refilter. The new check has been disabled for the cagra filter test.

Steps/Code to reproduce bug
Re-enable the check in ann_cagra.cuh and run cpp/build/gtests/NEIGHBORS_ANN_CAGRA_TEST --gtest_filter="*AnnCagraFilterTest*".

Expected behavior
The returned neighbor indices contain no duplicates for each query id.

FYI @tfeher @achirkin

[mfoerste4]

The initial occurrence is after calling into select_and_run for multi-cta.