fix: handle list-shape data in Firecrawl /search response (#24712)

Firecrawl /search returns either `{"data": [...]}` (flat list — v1, and
what frost19k reported on #23966) or `{"data": {"web": [...]}}` (v2,
current production). The parser only handled the dict shape:

    data = response.get('data') or {}
    results = data.get('web') or []

On a list-shape response, `data.get('web')` raised AttributeError,
caught by the function's outer try/except, and `search_firecrawl`
silently returned []. Web search worked against v2 endpoints but is one
upstream-format-change away from failing closed again. Accept either.

backend/open_webui/retrieval/web/firecrawl.py

@@ -197,8 +197,11 @@ def search_firecrawl(
             },
             timeout=count * 3 + 10,
         )
+        # Firecrawl /search has historically returned both `{"data": [...]}`
+        # (flat list, what v1 did and what frost19k reported under #23966)
+        # and `{"data": {"web": [...]}}` (current v2). Accept either.
         data = response.get('data') or {}
-        results = data.get('web') or []
+        results = data if isinstance(data, list) else (data.get('web') or [])
 
         if filter_list:
             from open_webui.retrieval.web.main import get_filtered_results