Update WordPress core Trac report 23 to easily discover "Popular Tickets"

[netweb]

Core currently has an unused "Popular Tickets" report, report 23 -> ​https://core.trac.wordpress.org/report/23 that returns empty and displays (Currently unused.)

As far as I know ​#WP12706 is the number one watched/starred/voted ticket with currently 123 "stars", though this may not be the case and another ticket is watched/starred/voted more, discovering the most watched/starred/voted tickets is not currently easily discoverable on Trac, we should fix this by updating this Trac report 23.

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If your a bbPress Trac admin you can peek at the bbPress same/similar/default report ​https://bbpress.trac.wordpress.org/report/23, though it appears this was a copy of the now non existent "core" report, the report fails because bbPress Trac does not include the "votes" table ( see #291 )

[SergeyBiryukov]

The query was referencing the old votes table, which apparently no longer exists. There is, however, a _ticket_subs table introduced during the work on #127.

By inspecting some other reports (specifically ​https://core.trac.wordpress.org/report/50) and open sourced parts of the notifications code, I have managed to fix the query :)

[netweb]

In Core Trac ​report 23 show all the popular things

Props SergeyBiryukov, Fixes #1204.

Boom, awesome, this is exactly what I envisioned, thanks Sergey :)