Your code above (the mapping) specifies that the column has a primary key and a non-clustered index. You then attempt to add a clustered index to another column when the primary key will already be clustered. EntityFamework creates all primary keys as clustered indexes.
According to my understanding, you cannot construct a non-clustered primary key without altering the migration; hence, you would need to do so.
.PrimaryKey(t => t.Id, null, true)