✅ Fixed filtering by producer/magazine on anime/manga search endpoints

[pushrbx]

Fixes #517
Currently if you search by producer or magazine on anime/manga search endpoints respectively together with other filter parameters, you won't get back any results because the database query for the search was constructed incorrectly. This PR fixes that problem.

Additional changes:

• Improved model factories to increase the randomness of the generated models.
• Added the model factory state overrides for filters "score", "magazines" and "producers", so getOverridesFromQueryStringParameters method will manufacture the correct models when asked with these params.
• Added test for the use case described in #517

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 52.63158% with 9 lines in your changes are missing coverage. Please review.

Project coverage is 57.76%. Comparing base (c425c32) to head (9342407).

Files	Patch %	Lines
app/Anime.php	50.00%	9 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #528 +/- ## ============================================ + Coverage 57.45% 57.76% +0.30% Complexity 1352 1352 ============================================ Files 339 339 Lines 5209 5209 ============================================ + Hits 2993 3009 +16 + Misses 2216 2200 -16 ```

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