[6.x] Set relation connection on eager loaded MorphTo

[yaim]

As a fix of bug described in issue #29935, this will pass the initial model's connection to the eager loaded MorphTo model that is using a default connection.

[Vercoutere]

@yaim

This appears to be a potentially breaking change for some applications.

Eager loading a morphTo relationship on a model that is being queried without global scopes, appears to apply global scopes anyway because of the call to $this->getConnection().

If I understand what's happening correctly, calling withoutGlobalScopes() on the morphTo relation seems to fix this issue for now.
I don't know what happens if the child in the morphTo relation were to have it's own global scopes applied, which you wouldn't want removed, so I'm not sure if this is the best course of action.

Let me know if you feel I should create an issue for this.

Tagging @PollieDev as he's been working with me on this issue.