Refactor collection and group suggestion handling to improve name comparison logic

Updated the CreateCollectionFromSuggestionCommandHandler and CreateGroupFromSuggestionCommandHandler to compare names in memory rather than using SQL queries for case-insensitive checks. This change addresses potential discrepancies with SQL's case sensitivity, particularly with special characters. Additionally, modified unit tests to use array syntax for assertions, enhancing readability and consistency across the test suite.

backend/tests/TeleWave.Application.Tests/Metadata/TmdbMetadataProviderTests.cs

@@ -97,7 +97,7 @@ public class TmdbMetadataProviderTests
         Assert.Equal("Сериал", show.Title);
         Assert.Equal(2001, show.Year);
         // Идентификатор впереди названия, безымянный жанр — только идентификатором.
-        Assert.Equal(new[] { "tmdb:28", "Боевик", "Драма", "tmdb:99" }, show.Genres);
+        Assert.Equal(["tmdb:28", "Боевик", "Драма", "tmdb:99"], show.Genres);
         // US приоритетнее RU, хотя в ответе идёт вторым.
         Assert.Equal("TV-14", show.ContentRating);
     }
@@ -236,7 +236,7 @@ public class TmdbMetadataProviderTests
 
         var seasons = await Provider(http).GetSeasonNumbersAsync("42", CancellationToken.None);
 
-        Assert.Equal(new[] { 1, 2 }, seasons);
+        Assert.Equal([1, 2], seasons);
     }
 
     [Fact]