Jetpack: optimize the Sharing module hook (#40128)

Make the Sharing module run the `template_redirect` action callback only when necessary.

Committed via a GitHub action: https://github.com/Automattic/jetpack/actions/runs/11781856359

Upstream-Ref: Automattic/jetpack@11ca6bd

CHANGELOG.md

@@ -26,6 +26,7 @@ This is an alpha version! The changes listed here are not final.
 - Fix Slideshow block width when used inside a Row block
 - Jetpack AI: fix image generation modals jumpiness by fitting boththe image sizes and the placeholder/empty image
 - Opengraph: minor bug fixing.
+- Optimize the Sharing module hook callback.
 - Remove old widget migration code.
 - Search: add ability to customize order of results
 - Sync: Added test for Full Sync sending modules in the order config is set

extensions/blocks/sharing-button/sharing-button.php

@@ -202,7 +202,11 @@ function sharing_process_requests() {
 		}
 	}
 }
-add_action( 'template_redirect', __NAMESPACE__ . '\sharing_process_requests', 9 );
+
+// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- Only checking for the data being present.
+if ( isset( $_GET['share'] ) ) {
+	add_action( 'template_redirect', __NAMESPACE__ . '\sharing_process_requests', 9 );
+}
 
 /**
  * Automatically add the Sharing Buttons block to the end of the Single Posts template.

modules/sharedaddy/sharing-service.php

@@ -930,7 +930,11 @@ function sharing_process_requests() {
 		}
 	}
 }
-add_action( 'template_redirect', 'sharing_process_requests', 9 );
+
+// phpcs:ignore WordPress.Security.NonceVerification.Recommended -- Only checking for the data being present.
+if ( isset( $_GET['share'] ) ) {
+	add_action( 'template_redirect', 'sharing_process_requests', 9 );
+}
 
 /**
  * Gets the url to customise the sharing buttons in Calypso.