Add self to HasCollection type param in Model

[thena-seer-sfg]

Summary

Psalm is giving me this error when trying to extend the Model class.
Extended template param TModel of Illuminate\Database\Eloquent\Collection<array-key, static> expects type Illuminate\Database\Eloquent\Model, type static given (see https://psalm.dev/183)

The proposed change solves the error by indicating that whatever type resolved by static should also resolve as self AKA Model, according to the Collection template requirement.

My composer.json has:

        "php": "^8.3",
        "laravel/framework": "^11.0",
...
        "vimeo/psalm": "5.26.1",
        "psalm/plugin-laravel": "^2.11"