Fix Core v3 Template Issues

[jakejackson1]

Description

This PR fixes:

1. Duplicate Product Table
2. PHP Notice due to bad form ID reference
3. Array key undefined reference

Testing instructions

Install the following template and configure on a form with a:

1. Section Break
2. HTML Field
3. Product field

onepage.php.txt

Verify there isn't a duplicate product table, or any PHP errors/warnings present.

Checklist:

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

Additional Comments

[codecov[bot]]

Codecov Report

Merging #1399 (4cc7ada) into development (d35f361) will decrease coverage by 16.02%. The diff coverage is 0.00%.

@@                Coverage Diff                 @@
##             development    #1399       +/-   ##
==================================================
- Coverage          93.30%   77.28%   -16.03%     
- Complexity             0     2898     +2898     
==================================================
  Files                 57      243      +186     
  Lines               1464    10102     +8638     
  Branches             370      370               
==================================================
+ Hits                1366     7807     +6441     
- Misses                90     2287     +2197     
  Partials               8        8               

Impacted Files	Coverage Δ
src/Helper/Fields/Field_V3_Products.php	0.00% <0.00%> (ø)
src/deprecated.php	16.09% <0.00%> (ø)
src/View/html/GravityForms/fieldset.php	80.48% <0.00%> (ø)
src/templates/config/legacy.php	50.00% <0.00%> (ø)
src/View/View_GravityForm_Settings_Markup.php	52.72% <0.00%> (ø)
src/Controller/Controller_Debug.php	95.00% <0.00%> (ø)
src/Helper/Fields/Field_Tax.php	0.00% <0.00%> (ø)
src/Helper/Fields/Field_Section.php	89.58% <0.00%> (ø)
src/Helper/Fields/Field_V3_Section.php	0.00% <0.00%> (ø)
src/Helper/Helper_Interface_Filters.php	0.00% <0.00%> (ø)
... and 178 more

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[jakejackson1]

Notify 6.4.4 customers in HS once this is merged and released.

[jakejackson1]

@jestonihpi could you test out this PR by following the instructions listed?

[jestonihpi]

Copy @jakejackson1