fix(theme): prevent parent to stay string

Author: gaetan-hexadog

src/Theme.php

@@ -49,7 +49,7 @@ class Theme
     /**
      * The Parent theme.
      */
-    protected string | Theme | null $parent;
+    protected string|Theme|null $parent = null;
 
     /**
      * The theme statud (enabled or not).
@@ -219,7 +219,7 @@ public function hasParent(): bool
     /**
      * Set parent Theme.
      */
-    public function setParent(string | Theme | null $theme): self
+    public function setParent(string|Theme|null $theme): self
     {
         $this->parent = empty($theme) ? null : $theme;
 
@@ -229,9 +229,9 @@ public function setParent(string | Theme | null $theme): self
     /**
      * Get parent Theme.
      */
-    public function getParent(): Theme | null
+    public function getParent(): Theme|null
     {
-        if (is_string($this->parent) && !empty($this->parent)) {
+        if (is_string($this->parent)) {
             $this->parent = ThemesManager::findByName($this->parent);
         }
 
@@ -359,7 +359,7 @@ public function url(string $url, bool $absolute = true): string
     /**
      * List theme's available layouts.
      *
-     * @return Collection
+     * @return \Illuminate\Support\Collection
      */
     public function listLayouts()
     {