[JENKINS-68934] Extract inline JS for optional blocks in configuration

core/src/main/resources/lib/form/checkbox.jelly

@@ -41,10 +41,10 @@ THE SOFTWARE.
       If this attribute is unspecified or null, it defaults to unchecked, otherwise checked.
     </st:attribute>
     <st:attribute name="id" />
-    <st:attribute name="onclick" />
+    <st:attribute name="onclick" deprecated="true" />
     <st:attribute name="class" />
     <st:attribute name="negative" />
-    <st:attribute name="readonly">
+    <st:attribute name="readonly" deprecated="true">
       If set to true, this will take precedence over the onclick attribute and prevent the state of the checkbox from being changed.
 
       Note: if you want an actual read only checkbox then add:

core/src/main/resources/lib/form/optional-block.js

@@ -0,0 +1,7 @@
+document.addEventListener('DOMContentLoaded', function() {
+  document.querySelectorAll('input.optional-block-event-item').forEach(function(el) {
+    el.addEventListener('click', function(e) {
+      updateOptionalBlock(el, true);
+    });
+  });
+});

core/src/main/resources/lib/form/optionalBlock.jelly

@@ -69,7 +69,8 @@ THE SOFTWARE.
       <div class="optionalBlock-container jenkins-form-item">
         <div class="help-sibling tr optional-block-start row-group-start ${attrs.inline?'':'row-set-start'}" hasHelp="${attrs.help!=null}"><!-- this ID marks the beginning -->
           <div class="jenkins-checkbox-help-wrapper">
-            <f:checkbox name="${attrs.name}" class="optional-block-control block-control" onclick="javascript:updateOptionalBlock(this,true)"
+            <st:adjunct includes="lib.form.optional-block"/>
+            <f:checkbox name="${attrs.name}" class="optional-block-control block-control optional-block-event-item"
                         negative="${attrs.negative}" checked="${attrs.checked}" field="${attrs.field}" title="${title}" />
             <f:helpLink url="${attrs.help}" featureName="${title}"/>
           </div>