Temp fixes the endpoint of the integration api

What does this MR do and why?

Fixes these main-jh failed jobs in https://jihulab.com/gitlab-cn/gitlab/-/jobs/7536689:

• rspec ./jh/spec/requests/api/integrations/feishu_bot_spec.rb
• rspec ./jh/spec/requests/api/integrations/dingtalk_spec.rb

Upstream has moved EE integration features into CE and removed the prepend ability, which JH relied on. For more information, please see:

• Upstream issue: https://gitlab.com/gitlab-org/gitlab/-/issues/355896
• Upstream MR: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/118289/diffs#98e14502d019b86eae7706566225db07fe93cbfa

The real fix is to add back the prepend ability. This merge request proposes a temporary solution to address the issue.

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

How to set up and validate locally

rspec ./jh/spec/requests/api/integrations/feishu_bot_spec.rb
rspec ./jh/spec/requests/api/integrations/dingtalk_spec.rb

MR acceptance checklist

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