Support value-converted parameters in raw SQL

It currently isn't possible to specify a value-converted type as a parameter in raw SQL. It seems like the pre-convention configuration `DefaultTypeMapping` should make this work:

```c#
protected override void ConfigureConventions(ModelConfigurationBuilder configurationBuilder)
{
configurationBuilder.DefaultTypeMapping()
.HasConversion(typeof(NameWrapperConverter));
}
```

... but I still get the exception:

```
Unhandled exception. System.InvalidOperationException: The current provider doesn't have a store type mapping for properties of type 'NameWrapper'.
at Microsoft.EntityFrameworkCore.Storage.RelationalTypeMappingSourceExtensions.GetMapping(IRelationalTypeMappingSource typeMappingSource, Type clrType) in /home/roji/projects/efcore/src/EFCore.Relational/Storage/RelationalTypeMappingSourceExtensions.cs:line 89
at Microsoft.EntityFrameworkCore.Storage.Internal.RawSqlCommandBuilder.Build(String sql, IEnumerable`1 parameters) in /home/roji/projects/efcore/src/EFCore.Relational/Storage/Internal/RawSqlCommandBuilder.cs:line 83
at Microsoft.EntityFrameworkCore.RelationalDatabaseFacadeExtensions.ExecuteSqlRaw(DatabaseFacade databaseFacade, String sql, IEnumerable`1 parameters) in /home/roji/projects/efcore/src/EFCore.Relational/Extensions/RelationalDatabaseFacadeExtensions.cs:line 244
at Microsoft.EntityFrameworkCore.RelationalDatabaseFacadeExtensions.ExecuteSqlRaw(DatabaseFacade databaseFacade, String sql, Object[] parameters) in /home/roji/projects/efcore/src/EFCore.Relational/Extensions/RelationalDatabaseFacadeExtensions.cs:line 159
at Microsoft.EntityFrameworkCore.RelationalDatabaseFacadeExtensions.ExecuteSqlInterpolated(DatabaseFacade databaseFacade, FormattableString sql) in /home/roji/projects/efcore/src/EFCore.Relational/Extensions/RelationalDatabaseFacadeExtensions.cs:line 191
```

Full repro

```c#
await using var ctx = new BlogContext();
await ctx.Database.EnsureDeletedAsync();
await ctx.Database.EnsureCreatedAsync();

ctx.Database.ExecuteSqlInterpolated($@"SELECT * FROM ""Blogs"" WHERE ""Name"" = {new NameWrapper { Name = "foo " }}");

public class BlogContext : DbContext
{
public DbSet Blogs { get; set; }

protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
=> optionsBuilder
.UseSqlServer(@"Server=localhost;Database=test;User=SA;Password=Abcd5678;Connect Timeout=60;ConnectRetryCount=0")
.LogTo(Console.WriteLine, LogLevel.Information)
.EnableSensitiveDataLogging();

protected override void ConfigureConventions(ModelConfigurationBuilder configurationBuilder)
{
configurationBuilder.DefaultTypeMapping()
.HasConversion(typeof(NameWrapperConverter));
}

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity().Property(b => b.Name)
.HasConversion(typeof(NameWrapperConverter));
}

class NameWrapperConverter : ValueConverter
{
public NameWrapperConverter()
: base(nw => nw.Name, s => new NameWrapper { Name = s })
{

}
}
}

public class Blog
{
public int Id { get; set; }
public NameWrapper Name { get; set; }
}

public class NameWrapper
{
public string Name { get; set; }
}
```

Raised by @juchom in https://github.com/npgsql/efcore.pg/issues/2259