Consider foreign key constraints with isRelationNullable (#1231)

* Consider foreign key constraints with isRelationNullable

* test: add belongsTo Variation

* command: composer test-regenerate

tests/Console/ModelsCommand/Relations/Models/BelongsToVariation.php

@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Barryvdh\LaravelIdeHelper\Tests\Console\ModelsCommand\Relations\Models;
+
+use Illuminate\Database\Eloquent\Model;
+use Illuminate\Database\Eloquent\Relations\BelongsTo;
+
+class BelongsToVariation extends Model
+{
+    public function notNullColumnWithForeignKeyConstraint(): BelongsTo
+    {
+        return $this->belongsTo(self::class, 'not_null_column_with_foreign_key_constraint');
+    }
+
+    public function notNullColumnWithNoForeignKeyConstraint(): BelongsTo
+    {
+        return $this->belongsTo(self::class, 'not_null_column_with_no_foreign_key_constraint');
+    }
+
+    public function nullableColumnWithForeignKeyConstraint(): BelongsTo
+    {
+        return $this->belongsTo(self::class, 'nullable_column_with_foreign_key_constraint');
+    }
+
+    public function nullableColumnWithNoForeignKeyConstraint(): BelongsTo
+    {
+        return $this->belongsTo(self::class, 'nullable_column_with_no_foreign_key_constraint');
+    }
+}