feat: initialize usage tracker

Signed-off-by: Bart Jaskulski <bjaskulski@protonmail.com>

CHANGELOG.md

+## [Unreleased]
+### Changed
+- Usage tracker is initialized by the library after all plugin's hookables are registered.
+
 ## [1.1.0] - 2022-11-23
 ### Added
 - Compatibility with WooCommerce High-Performance Order Storage (HPOS)

src/Initialization/Simple/SimpleFreeStrategy.php

@@ -52,6 +52,9 @@ class SimpleFreeStrategy implements InitializationStrategy {
 
 		$this->store_plugin( $this->plugin );
 		$this->init_plugin( $this->plugin );
+		// Flush usage tracker late, to remain backward compatible with plugins which could instantiate
+		// the tracker on their own through `wpdesk_tracker_instance` filter.
+		$this->get_tracker_instance();
 
 		return $this->plugin;
 	}

src/Initialization/Simple/SimplePaidStrategy.php

@@ -65,6 +65,9 @@ class SimplePaidStrategy implements InitializationStrategy {
 			}
 			$this->store_plugin( $this->plugin );
 			$this->init_plugin( $this->plugin );
+			// Flush usage tracker late, to remain backward compatible with plugins which could instantiate
+			// the tracker on their own through `wpdesk_tracker_instance` filter.
+			$this->get_tracker_instance();
 		}, $priority_before_flow_2_5_after_2_6 = -45);
 
 		return $this->plugin;