Search: enable search analytics tracking for wpcom sites

We had to disable the search analytics on wpcom sites because our anonymization method was breaking other applications where it was not supposed to be fully anonymous.

Hopefully this is just turning back on what we had before, but probably should do some testing around it also.

See: p4qSXL-3xT-p2

No file or test is named; start by reviewing the prior search-analytics and anonymization change referenced by P4 (p4qSXL-3xT-p2), then locate the wpcom search tracking entry point. Test search analytics on wpcom sites and other affected applications. Done means analytics is enabled for wpcom sites without breaking applications that require non-anonymous behavior.

Written by the indexing model from the issue text.