Fix layout column problem when GF Styles Pro enabled

[jakejackson1]

Description

Move the grid CSS classes first in the class order, so that they aren't removed due to an mPDF processing bug when there are a lot of classes.

Testing instructions

1. Create a form with multiple drag and drop columns
2. On fields in columns, add 10 different CSS classes to those field
3. View the PDF and see those fields are not in columns.

This problem occurs because we needed to limit the number of CSS classes that can be included on fields.

Checklist:

• [x] 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[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 77.03%. Comparing base (b9d16b6) to head (46c4a1e).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## development #1498 +/- ## ============================================ Coverage 77.03% 77.03% ============================================ Files 243 243 Lines 12447 12447 Branches 370 370 ============================================ Hits 9589 9589 Misses 2850 2850 Partials 8 8 ```

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