biology/kallisto: Revert to 0.46.1

0.46.2 has long-standing regressions that are not being addressed, including
a seg fault when using --genomebam.
Also revert to bundled htslib in preparation for biology/htslib upgrade
to 1.10. Kallisto source contains modified bits of htslib 1.4.1 that are
incompatible with htslib > 1.9.