Fix hictk dump -t bins for files in .scool format

[robomics]

Closes #112

[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (082348e) 84.66% compared to head (68d660b) 84.64%.
Report is 2 commits behind head on main.

Files	Patch %	Lines
src/hictk/cli/cli_dump.cpp	83.33%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #114      +/-   ##
==========================================
- Coverage   84.66%   84.64%   -0.03%     
==========================================
  Files         114      114              
  Lines        9125     9130       +5     
==========================================
+ Hits         7726     7728       +2     
- Misses       1399     1402       +3     

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