Improve testing init, clean up webhook tests (#37412)

Avoid webhook test fixtures affect other tests (be triggered)

Also fixed more testing problems including path init, global config
pollution & conflict

---------

Signed-off-by: silverwind <me@silverwind.io>
Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: wxiaoguang <2114189+wxiaoguang@users.noreply.github.com>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: silverwind <me@silverwind.io>

models/fixtures/hook_task.yml

@@ -1,39 +1,2 @@
--
-  id: 1
-  hook_id: 1
-  uuid: uuid1
-  is_delivered: true
-  is_succeed: false
-  request_content: >
-    {
-      "url": "/matrix-delivered",
-      "http_method":"PUT",
-      "headers": {
-        "X-Head": "42"
-      },
-      "body": "{}"
-    }
-
--
-  id: 2
-  hook_id: 1
-  uuid: uuid2
-  is_delivered: true
-
--
-  id: 3
-  hook_id: 1
-  uuid: uuid3
-  is_delivered: true
-  is_succeed: true
-  payload_content: '{"key":"value"}' # legacy task, payload saved in payload_content (and not in request_content)
-  request_content: >
-    {
-      "url": "/matrix-success",
-      "http_method":"PUT",
-      "headers": {
-        "X-Head": "42"
-      }
-    }
-
+[]
 # DO NOT add more test data in the fixtures, test case should prepare their own test data separately and clearly