Fix wrong band width calculation under some circumstances

[padix-key]

Currently align_banded() may return local alignments even if local=False under rare circumstances.

The problem was that band diagonals are trimmed to the size of the sequences (just to save memory), but under this cicumstances the band width is not updated. This allowed the trace to 'escape' the alignment band for low-scoring alignments leading to a premature traceback termination and thus local alignments instead of semi-global ones.

[codspeed-hq]

CodSpeed Performance Report

Merging #723 will not alter performance

_{Comparing padix-key:alignment-fix (965e799) with main (0acb143)}

Summary

✅ 47 untouched benchmarks