Improve column support when there is a spacer

[jakejackson1]

Description

Better calculate when Gravity Forms would insert a spacer into the form, so we can correctly end a row in the PDF.

Testing instructions

1. Create a form with drag and drop columns
2. Set the width of a field in a column to only take up some of the space
3. Add additional rows and columns with a similar configuration
4. Add a PDF to the form
5. Preview the PDF

Checklist:

• I've tested the code.
• My code is easy to read, follow, and understand
• My code follows the accessibility standards.
• My code has proper inline documentation / docblocks.

Additional Comments

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 4 lines in your changes missing coverage. Please review.

Project coverage is 75.68%. Comparing base (bb5a359) to head (af25986).
Report is 5 commits behind head on hot-patch.

Files with missing lines	Patch %	Lines
src/Helper/Helper_Field_Container_Gf25.php	0.00%	4 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##           hot-patch    #1590      +/-   ##
=============================================
- Coverage      75.70%   75.68%   -0.02%     
=============================================
  Files            251      251              
  Lines          13606    13609       +3     
  Branches         370      370              
=============================================
  Hits           10300    10300              
- Misses          3298     3301       +3     
  Partials           8        8              

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