MDL-77337 analytics: Added class properties that are not declared.

In PHP 8.2 and later, setting a value to an undeclared class property is
deprecated and emits a deprecation notice.
So we need to add missing class properties that still need to be declared.

analytics/classes/course.php

@@ -126,6 +126,9 @@ class course implements \core_analytics\analysable {
      */
     protected $ntotallogs = null;
 
+    /** @var int Store current Unix timestamp. */
+    protected int $now = 0;
+
     /**
      * Course manager constructor.
      *