Use registry.gitlab.com for CI_TEMPLATE_REGISTRY_HOST in HK SaaS

What does this MR do and why?

Related to issue #2707 (closed)

In JH, we use registry.gitlab.cn for CI_TEMPLATE_REGISTRY_HOST so we can use docker images stored in Tencent cloud registry.

But in HK, it's better to use registry.gitlab.com.

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Before	After

How to set up and validate locally

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