Regression: Link field title autocomplete setting not respected

Problem/motivation

Code changes in #3538856: Field widget broken if there's multiple link fields, one without link text enabled failed to scope when to apply the "Automatically populate link text from entity label" configuration option properly by removing code that looked for data-linkit-widget-title-autofill-enabled.

As a result, all Link fields on sites using 7.0.8 or later receive the automatic population behavior regardless of configuration.

Steps to reproduce

1. Create a link field with the Linkit widget, configured with "Automatically populate link text from entity label" set to "No"
2. Populate the URL using autocomplete.
3. Observe that the link title is autopopulated despite the configuration setting

Proposed resolution

diff --git a/js/linkit.autocomplete.js b/js/linkit.autocomplete.js
index e790077..9fd28cc 100644
--- a/js/linkit.autocomplete.js
+++ b/js/linkit.autocomplete.js
@@ -76,7 +76,7 @@
       const linkSelector = event.target.getAttribute('data-drupal-selector');
       if (linkSelector && linkSelector.endsWith('-uri')) {
         const titleSelector = linkSelector.slice(0, -4) + '-title';
-        const $linkTitle = $(`[data-drupal-selector="${titleSelector}"]`, $context);
+        const $linkTitle = $(`[data-linkit-widget-title-autofill-enabled][data-drupal-selector="${titleSelector}"]`, $context);
         // Don't overwrite an existing label unless we already replaced it
         // before.
         if ($linkTitle.length > 0 && (!$linkTitle.val() || $linkTitle.hasClass('link-widget-title--auto'))) {