Revert code of "Gitlab::Source.blob_url"

What does this MR do and why?

Fix pipeline: https://jihulab.com/gitlab-cn/gitlab/-/pipelines/1220202/failures

1. rspec-ee system pg13 4/10
   这个报错先跳过，不影响 JiHu 的功能。
   报错原因：Upstream Spec 中默认用了 google_oauth2 来登录（saas_registration_helpers.rb#L51），JiHu 是不支持它的。等会给它覆盖为 JiHu 支持的登录选项即可。

2. rspec-jh unit pg12
   Upstream 在上周五 Revert 掉了之前的 blob_url 改动：MR，所以 JiHu 在上周五做的适配代码，在这个 MR 里也 Revert 掉。

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