feat: add method to retrieve theme by code

Author: dermatz

src/Model/ThemeList.php

@@ -27,4 +27,15 @@ public function getAllThemes(): array
     {
         return $this->magentoThemeList->getItems();
     }
+
+    public function getThemeByCode(string $code): ?\Magento\Framework\View\Design\ThemeInterface
+    {
+        $themes = $this->getAllThemes();
+        foreach ($themes as $theme) {
+            if ($theme->getCode() === $code) {
+                return $theme;
+            }
+        }
+        return null;
+    }
 }