Plugins: Make delete plugin message less scary.

This adds a check if the plugin actually has an uninstall routine before saying that its data will be deleted too.

Props samful, joostdevalk, joyously, Chouby, SergeyBiryukov.
Fixes #50346.

git-svn-id: https://develop.svn.wordpress.org/trunk@48451 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/includes/class-wp-plugins-list-table.php

@@ -942,6 +942,10 @@ class WP_Plugins_List_Table extends WP_List_Table {
 			$class .= ' paused';
 		}
 
+		if ( is_uninstallable_plugin( $plugin_file ) ) {
+			$class .= ' is-uninstallable';
+		}
+
 		printf(
 			'<tr class="%s" data-slug="%s" data-plugin="%s">',
 			esc_attr( $class ),