[FIX] Can not search using a string operator on column id

The branch name is badly named but the issue is all about searching using an Odoo domain on a column ```id```. It doesn't work if you use a PostgreSQL string operator because the code that handles it is bypassed by this special case that is useless.

This fix is good for master too.
Hello @xmo-odoo ,

Could you have a look at this?

So basically I removed the code in expression.py that make the comparison with the column id has a specific behavior (diff below). It should be good since it seems we don't really use specific behavior for "magic columns" anymore. But it made your test fails because the message change.

The message changed because when the domain is translated to SQL, the value (here: "foo") is given to _symbol_set() of the type of the column id (integer) and it tries to cast using int().

Best