Can't drop primary key in table with foreign key constraint on other column

Dolt version 1.80.2

Repro:

Foreign key checks **must be off**

```
% dolt init
Successfully initialized dolt data repository.
% dolt sql
test/main> CREATE TABLE test1 (id int primary key);
Query OK, 0 rows affected (0.01 sec)
test/main*> CREATE TABLE test2 (id INT PRIMARY KEY, ref INT, CONSTRAINT fk FOREIGN KEY (ref) REFERENCES test1(id));
Query OK, 0 rows affected (0.01 sec)
test/main*> ALTER TABLE test2 DROP PRIMARY KEY;
error: can't drop index 'PRIMARY': needed in foreign key constraint fk
```

Works in mysql.

You can drop primary keys of the same table if it doesn't have the foreign key constraint.