[3.0] Let the news feed run without a current board

[albertlast]

Description

?action=.xml;sa=news is an error page on every forum unless it is scoped to a board:

Typed static property SMF\Board::$info must not be accessed before initialization
                                                    Sources/Actions/Feed.php:748

getXmlNews() puts Board::$info->id straight into the query parameters:

[
	'current_board' => Board::$info->id,
	'is_approved' => 1,
	…
]

The WHERE clause only uses that parameter when there is a board, and the conditions deciding it go through empty(), which tolerates an uninitialised typed property:

(empty(Board::$info->id) ? '' : '
	AND t.id_board = {int:current_board}')

The parameter array does not — it reads the property outright, and a feed for the whole forum has no current board to read. So the site-wide news feed dies while the per-board one works.

getXmlRecent(), a few hundred lines further down in the same file, already does it the right way, and this now matches:

$current_board = isset(Board::$info) ? Board::$info->id : 0;

Checked

As a guest on the running forum, before:

?action=.xml;sa=news             → "An error has occurred", 0 items
?action=.xml;sa=news;board=1     → 1 item

after:

?action=.xml;sa=news             → 5 <item>
?action=.xml;sa=news;board=1     → items
?action=.xml;sa=news;type=atom   → <entry>
?action=.xml;sa=recent           → items

This one is worth a second look precisely because phplint and php-cs-fixer both pass on it and nothing in the codebase reads the feed — it only fails when something asks for the URL. Found by sweeping a stock forum's pages as a guest; every earlier sweep in this series ran as an admin and never requested it.

Issues References (Fixes|Related|Closes)

Related to #7933