Use proxied_site for geo proxied clone urls

What does this MR do and why?

From the comment here:

Currently, the code assumes if GEO_PROXIED_HEADER is 1, then GEO_PROXIED_EXTRA_DATA_HEADER is present and decoding it will succeed. We should instead go through with decoding the data and getting proxied_site in order to decide whether to use proxied_site here.

Use proxied_site instead of proxied_request to ensure that proxied site's decoding is successful.

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Related to #404497 (closed)