Make GiftCardConfigurationProvider always return GiftCardConfiguration

[loevgaard]

Fixes #220

I think this PR makes a lot of sense given the name of the provider. You expect the GiftCardConfigurationProvider to actually provide a GiftCardConfiguration.

[codecov]

Codecov Report

Merging #221 (e8d3bfd) into 0.12.x (d4a716c) will decrease coverage by 0.70%.
The diff coverage is 19.29%.

❗ Current head e8d3bfd differs from pull request most recent head 9d1a5f4. Consider uploading reports for the commit 9d1a5f4 to get more accurate results

@@             Coverage Diff              @@
##             0.12.x     #221      +/-   ##
============================================
- Coverage     50.23%   49.53%   -0.71%     
- Complexity      532      534       +2     
============================================
  Files           102      103       +1     
  Lines          1696     1716      +20     
============================================
- Hits            852      850       -2     
- Misses          844      866      +22     

Impacted Files	Coverage Δ
...pi/Controller/Action/DownloadGiftCardPdfAction.php	87.50% <ø> (-12.50%)	⬇️
...rc/Controller/Action/DownloadGiftCardPdfAction.php	0.00% <ø> (ø)
...c/Doctrine/ORM/GiftCardConfigurationRepository.php	0.00% <0.00%> (ø)
src/Provider/GiftCardConfigurationProvider.php	0.00% <0.00%> (ø)
src/DependencyInjection/Configuration.php	100.00% <100.00%> (ø)
src/Factory/GiftCardFactory.php	100.00% <100.00%> (ø)
src/Model/GiftCardChannelConfiguration.php	73.33% <100.00%> (ø)

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[Roshyo]

I like this idea, it will ease the work to configure the plugin