Refa: align chat and search restful APIs (#14229)

### What problem does this PR solve?

Refactor /api/v1/chats to be more RESTful.

### Type of change

- [x] Refactoring

---------

Co-authored-by: Jin Hai <haijin.chn@gmail.com>

test/testcases/test_web_api/test_search_app/test_search_routes_unit.py

@@ -40,6 +40,13 @@ class _DummyAtomic:
         return False
 
 
+class _StubResponse:
+    def __init__(self, data=None, mimetype=None):
+        self.data = data
+        self.mimetype = mimetype
+        self.headers = {}
+
+
 class _Args(dict):
     def get(self, key, default=None):
         return super().get(key, default)
@@ -111,6 +118,7 @@ def _load_search_api(monkeypatch):
 
     quart_mod = ModuleType("quart")
     quart_mod.request = SimpleNamespace(args=_Args())
+    quart_mod.Response = _StubResponse
     monkeypatch.setitem(sys.modules, "quart", quart_mod)
 
     common_pkg = ModuleType("common")
@@ -201,6 +209,15 @@ def _load_search_api(monkeypatch):
     search_service_mod.SearchService = _SearchService
     monkeypatch.setitem(sys.modules, "api.db.services.search_service", search_service_mod)
 
+    dialog_service_mod = ModuleType("api.db.services.dialog_service")
+
+    async def _async_ask(*_args, **_kwargs):
+        if False:
+            yield None
+
+    dialog_service_mod.async_ask = _async_ask
+    monkeypatch.setitem(sys.modules, "api.db.services.dialog_service", dialog_service_mod)
+
     user_service_mod = ModuleType("api.db.services.user_service")
 
     class _TenantService: