fix(extend): 修复未传入 extends 不存在缺省值的问题

src/Service/ExtendService.php

@@ -24,13 +24,10 @@ class ExtendService
         array|string|null $params = null
     ): array {
         $params ??= $request?->getQueryParams();
-        $extends = $params['extends'] ?? null;
-        if (!empty($extends)) {
-            $extends = explode(',', $extends);
-            return Context::set(self::class, array_map('trim', $extends));
-        }
+        $extends = explode(',', $params['extends'] ?? '');
+        $extends = array_map('trim', $extends);
 
-        return [];
+        return Context::set(self::class, array_filter($extends));
     }
 
 
@@ -57,6 +54,6 @@ class ExtendService
      */
     public function hasExtend(string $field): bool
     {
-        return $this->utils->inArray($field, Context::get(self::class));
+        return $this->utils->inArray($field, Context::get(self::class) ?? []);
     }
 }