[Collection] The aggregate group for Collection extension is no more

Just include the standard one in the aggregate. Collection is very
user-facing, should maybe added to Wikimedia main in followup.

<https://translatewiki.net/wiki/Thread:Support/The_Collection_extension_not_listed_under_%E2%80%9CExtensions_used_by_Wikimedia%E2%80%9D>

Change-Id: I7b1529786df132680529b475f6db707c672724f1
Merge "[Collection] The aggregate group for Collection extension is no more"