minor #450 fix product not assigned to channel error message (CSchulz)

This PR was merged into the 1.0-dev branch.

Discussion
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I was wondering why querying an existing product results into a channel not found error.

(Could be possible that there will be some test failures, I will fix them soon).

Commits
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94f6c96 fix product not assigned to channel error message

src/ViewRepository/Product/ProductDetailsViewRepository.php

@@ -58,7 +58,7 @@ public function findOneByCode(string $productCode, string $channelCode, ?string
         $product = $this->productRepository->findOneByCode($productCode);
 
         Assert::notNull($product, sprintf('Product with code %s has not been found.', $productCode));
-        Assert::true($product->hasChannel($channel), sprintf('Channel with code %s has not been found.', $channelCode));
+        Assert::true($product->hasChannel($channel), sprintf('Product with code %s has not been found for channel %s.', $productCode, $channelCode));
 
         return $this->productViewFactory->create($product, $channel, $localeCode);
     }