information_schema.table_constraints and key_column_usage always list "memory" for table_catalog on attached databases - CONSTRAINTS are not then well export

Working on an attached sqlite database :
```
con = duckdb.connect()

con.execute("ATTACH 'california_schools.sqlite' as cs (TYPE sqlite)")

con.execute("USE cs")

res = con.execute("SELECT * FROM information_schema.table_constraints").fetchall()

print(res)
```

Here an error occured adding to use information_schema on "memory" :
```
CatalogException Traceback (most recent call last)

Cell In[187], line 1

----> 1 res = con.execute("SELECT * FROM information_schema.table_constraints").fetchall()

2 print(res)

CatalogException: Catalog Error: Table with name table_constraints does not exist!

Did you mean "memory.information_schema.table_constraints"?

LINE 1: SELECT * FROM information_schema.table_constraints
```

When adding it and using it as requiered, the return list is empty whereas constraints keys well exist in database.