Use boolean() instead of filled()

[reinink]

This PR updates the LoginRequest to use the request boolean() method instead of filled() when determining if the user should be remembered.

The primary issue with filled() is that it will return true if remember is false (in a JSON request). This is common when working with Inertia where you have a boolean remember data value.

Using boolean() works for the Blade approach as well, since the underlying FILTER_VALIDATE_BOOLEAN check returns true for the value "on".

[driesvints]

@reinink does the boolean change still works for apps which have already published the stubs?

[reinink]

@driesvints Yup! Using the new boolean() method:

In Blade templates, the remember value is either "on", which resolves to true, or is missing, which resolves to false.

In Inertia page components, the previous transform() done in the Login.vue component basically makes it behave just like the Blade templates, where the remember value is either "on", which resolves to true, or is "" (an empty string), which resolves to false.

Meaning, this should be a non-breaking change for those who have already published the stubs.