Remove event attributes from upgrade code.

themes/bootstrap3/templates/upgrade/fixanonymoustags.phtml

@@ -22,5 +22,14 @@ an administrator) to associate with old anonymous tags.</p>
 
 <form method="post" action="<?=$this->url('upgrade-fixanonymoustags')?>">
   <?=$this->transEsc('Username') ?>: <input type="text" name="username" /> <input type="submit" name="submit" value="<?=$this->transEsc('Submit') ?>" /><br /><br />
-  <input type="submit" name="skip" value="<?=$this->transEsc('skip_step') ?>." onclick="return confirm('<?=$this->transEsc('skip_confirm') ?>');"/>
+  <input type="submit" name="skip" id="skip" value="<?=$this->transEsc('skip_step') ?>." />
 </form>
+<?php
+$skipText = $this->transEsc('skip_confirm');
+$script = <<<JS
+$('#skip').click(function(e) {
+    return confirm('${skipText}');
+});
+JS;
+?>
+<?=$this->inlineScript(\Laminas\View\Helper\HeadScript::SCRIPT, $script, 'SET');

themes/bootstrap3/templates/upgrade/fixduplicatetags.phtml

@@ -21,5 +21,14 @@ otherwise, it is recommended that you fix these.  Click Submit to proceed.</p>
 
 <form method="post" action="<?=$this->url('upgrade-fixduplicatetags')?>">
   <input type="submit" name="submit" value="<?=$this->transEsc('Submit') ?>" /><br /><br />
-  <input type="submit" name="skip" value="<?=$this->transEsc('skip_step') ?>." onclick="return confirm('<?=$this->transEsc('skip_confirm') ?>');"/>
+  <input type="submit" name="skip" value="<?=$this->transEsc('skip_step') ?>." id="skip" />
 </form>
+<?php
+$confirmText = $this->transEsc('skip_confirm');
+$script = <<<JS
+$('#skip').click(function(e) {
+  return confirm('${confirmText}');
+});
+JS;
+?>
+<?=$this->inlineScript(\Laminas\View\Helper\HeadScript::SCRIPT, $script, 'SET');

themes/bootstrap3/templates/upgrade/fixmetadata.phtml

@@ -15,5 +15,14 @@ but it will improve the user experience by allowing proper sorting of favorites
 
 <form method="post" action="<?=$this->url('upgrade-fixmetadata')?>">
   <input type="submit" name="submit" value="<?=$this->transEsc('fix_metadata') ?>." /><br /><br />
-  <input type="submit" name="skip" value="<?=$this->transEsc('skip_fix_metadata') ?>." onclick="return confirm('<?=$this->transEsc('skip_confirm') ?>');"/>
+  <input type="submit" name="skip" value="<?=$this->transEsc('skip_fix_metadata') ?>." id="skip" />
 </form>
+<?php
+$confirmText = $this->transEsc('skip_confirm');
+$script = <<<JS
+$('#skip').click(function(e) {
+  return confirm('${confirmText}');
+});
+JS;
+?>
+<?=$this->inlineScript(\Laminas\View\Helper\HeadScript::SCRIPT, $script, 'SET');