[11.x] Merge in eager loads from nested where queries

[ollieread]

This PR merges in any eager loads from nested where clauses, so that withWhereHas can be used within a nested where.

[AndreaBellini23]

After updating to v11.42.0, which implements these changes, a query like

return $query->withWhereHas('model:column', function ($query) {
                            // something ;
                        });

throws a RelationNotFoundException "Call to undefined relationship [model:column] on model [App\Models{model}]
But if I remove the ":column" in withWhereHas, I don't get any exception.

I'm not sure if now this a correct behaviour, so I'm writing this comment before creating an issue.

[ollieread]

After updating to v11.42.0, which implements these changes, a query like

return $query->withWhereHas('model:column', function ($query) {
                            // something ;
                        });

throws a RelationNotFoundException "Call to undefined relationship [model:column] on model [App\Models{model}] But if I remove the ":column" in withWhere has, I don't get any exception.

I'm not sure if now this a correct behaviour, so I'm writing this comment before creating an issue.

I'll look into this today for you. It may be worth creating an issue anyway, but link to this PR and tag me in it. I'll see if I can figure out what's happening.