Fix template path in Grid config

[shochdoerfer]

The template paths are lowercase for Sylius 2.x

[codecov]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 10.81%. Comparing base (c081a12) to head (104dacf).
⚠️ Report is 4 commits behind head on 1.x.

Files with missing lines	Patch %	Lines
...pendencyInjection/SetonoSyliusCalloutExtension.php	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##                1.x     #117   +/-   ##
=========================================
  Coverage     10.81%   10.81%           
  Complexity      272      272           
=========================================
  Files            49       49           
  Lines          1119     1119           
=========================================
  Hits            121      121           
  Misses          998      998           

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