feat: Half image focus

[g123k]

When the barcode decoder uses the half image decoder, the camera should focus in this area.
Kind of fix #1384

[codecov-commenter]

Codecov Report

Merging #1579 (5df70ce) into develop (2ea0da3) will decrease coverage by 0.00%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           develop   #1579      +/-   ##
==========================================
- Coverage     8.86%   8.85%   -0.01%     
==========================================
  Files          161     161              
  Lines         6623    6629       +6     
==========================================
  Hits           587     587              
- Misses        6036    6042       +6     

Impacted Files	Coverage Δ
...es/smooth_app/lib/pages/scan/ml_kit_scan_page.dart	0.90% <0.00%> (-0.06%)	⬇️

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[M123-dev]

Looks good, I'm unable to tell from the documentation if a certain focus point doesn't just switch back to manual (That was my intuition when I first saw the setFocusPoint method) but let's try

[teolemon]

good to merge ?

[g123k]

@teolemon I think so