fix: boolean filter gave overly large buffers to Bitmap::from_u8_vec

[orlp]

Fixes #14914.

This only patches the what triggers this problem however, the real problem is that MutableBitmap has the following invariant:

// invariant: length.saturating_add(7) / 8 == buffer.len();

But it does nothing to ensure that invariant is true during initialization (and I haven't yet checked if it maintains it).

From a cursory glance it does seem to maintain the invariant, and now I also made sure it satisfies the invariant during initialization.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 81.01%. Comparing base (de5bad0) to head (0b31177).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #14924      +/-   ##
==========================================
- Coverage   81.01%   81.01%   -0.01%     
==========================================
  Files        1332     1332              
  Lines      172874   172870       -4     
  Branches     2458     2458              
==========================================
- Hits       140058   140051       -7     
- Misses      32347    32350       +3     
  Partials      469      469              

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