fix: remove connection-overriding constructors from Model and Setting

The constructors in Model.php and Setting.php both set:

    $this->connection = config('fleetbase.connection.db', 'mysql');

On main, the wrong config key ('fleetbase.db.connection') returned null,
making the constructors effectively no-ops — models without an explicit
$connection declaration correctly fell back to database.default, which
sandbox mode switches to 'sandbox'. The typo fix made the constructors
actively harmful by always forcing 'mysql', breaking sandbox switching
for every model that does not declare its own $connection.

The correct fix is to remove both constructors entirely:
- Models that declare $connection = 'mysql' (User, Company, Invite, etc.)
  have that value set by PHP at class instantiation — no constructor needed.
- Models without an explicit $connection (ApiCredential, CompanyUser, etc.)
  correctly inherit null from Eloquent and follow database.default, which
  is 'sandbox' in sandbox mode and 'mysql' otherwise.

The Invite model is handled separately via getConnectionName() override.

Author: Ronald A Richardson

src/Models/Model.php

@@ -30,20 +30,6 @@ class Model extends EloquentModel
     public const UUID_COLUMN      = 'uuid';
     public const PUBLIC_ID_COLUMN = 'public_id';
 
-    /**
-     * Create a new instance of the model.
-     *
-     * @param array $attributes the attributes to set on the model
-     *
-     * @return void
-     */
-    public function __construct(array $attributes = [])
-    {
-        parent::__construct($attributes);
-
-        $this->connection = config('fleetbase.connection.db', 'mysql');
-    }
-
     /**
      * The primary key for the model.
      *

src/Models/Setting.php

@@ -20,20 +20,6 @@ class Setting extends EloquentModel
     use Searchable;
     use Filterable;
 
-    /**
-     * Create a new instance of the model.
-     *
-     * @param array $attributes the attributes to set on the model
-     *
-     * @return void
-     */
-    public function __construct(array $attributes = [])
-    {
-        parent::__construct($attributes);
-
-        $this->connection = config('fleetbase.connection.db', 'mysql');
-    }
-
     /**
      * No timestamp columns.
      *