Address review: tighten Value-quoting assertion and drop off-topic entity test

Match the alias-qualified `."Value"` pattern instead of bare `"Value"` so
the assertion no longer matches the user-supplied raw SQL substring and
genuinely verifies EF Core's outer projection quotes the identifier.

Remove EntitySingleOrDefaultQuotesIdentifiers — it has no Value column,
asserts nothing about SQL content, and the Take(1) before
SingleOrDefaultAsync was redundant.

Author: fdcastel

src/FirebirdSql.EntityFrameworkCore.Firebird.Tests/Query/ElementaryTests.cs

@@ -218,7 +218,7 @@ public async Task SqlQueryScalarSingleQuotesValueColumn()
 			var query = db.Database.SqlQueryRaw<int>(@"SELECT 1 AS ""Value"" FROM RDB$DATABASE");
 			Assert.DoesNotThrowAsync(() => query.SingleAsync());
 			var sql = db.LastCommandText;
-			StringAssert.Contains(@"""Value""", sql);
+			StringAssert.Contains(@".""Value""", sql);
 		}
 	}
 
@@ -230,7 +230,7 @@ public async Task SqlQueryScalarSingleOrDefaultQuotesValueColumn()
 			var query = db.Database.SqlQueryRaw<int>(@"SELECT 1 AS ""Value"" FROM RDB$DATABASE");
 			Assert.DoesNotThrowAsync(() => query.SingleOrDefaultAsync());
 			var sql = db.LastCommandText;
-			StringAssert.Contains(@"""Value""", sql);
+			StringAssert.Contains(@".""Value""", sql);
 		}
 	}
 
@@ -242,17 +242,7 @@ public async Task SqlQueryScalarComposedWhereQuotesValueColumn()
 			var query = db.Database.SqlQueryRaw<int>(@"SELECT 1 AS ""Value"" FROM RDB$DATABASE").Where(x => x > 0);
 			Assert.DoesNotThrowAsync(() => query.LoadAsync());
 			var sql = db.LastCommandText;
-			StringAssert.Contains(@"""Value""", sql);
-		}
-	}
-
-	[Test]
-	public async Task EntitySingleOrDefaultQuotesIdentifiers()
-	{
-		await using (var db = await GetDbContext<SelectContext>())
-		{
-			var query = db.Set<MonAttachment>().OrderBy(x => x.AttachmentId).Take(1);
-			Assert.DoesNotThrowAsync(() => query.SingleOrDefaultAsync());
+			StringAssert.Contains(@".""Value""", sql);
 		}
 	}
 }