luci: Make password reveal work with passsword managers

Password managers (like LastPass etc) tend to add additional elements
into the DOM for their own context menus. If this happens between the
hide/reveal button and the password input, then the logic to reveal the
password breaks.

This change updates the onclick handler to look backward in the DOM for
the first sibling that is an input, and to then toggle the password/text
type on that element.

This change deliberately only updates the main ui.js file, not any
application files.

Signed-off-by: Andrew Dodd <andrew.john.dodd@gmail.com>

modules/luci-base/htdocs/luci-static/resources/ui.js

@@ -384,8 +384,18 @@ const UITextfield = UIElement.extend(/** @lends LuCI.ui.Textfield.prototype */ {
 					'title': _('Reveal/hide password'),
 					'aria-label': _('Reveal/hide password'),
 					'click': function(ev) {
-						const e = this.previousElementSibling;
-						e.type = (e.type === 'password') ? 'text' : 'password';
+						let e = this.previousElementSibling;
+						// DOM manipulation (e.g. by password managers) may have inserted other
+						// elements between the reveal button and the input. This searches for
+						// the first previous sibling that is also an input.
+						while (e && e.tagName !== 'INPUT') {
+							e = e.previousElementSibling;
+						}
+						if (e) {
+							e.type = (e.type === 'password') ? 'text' : 'password';
+						} else {
+							console.error("unable to find input corresponding to reveal/hide button");
+						}
 						ev.preventDefault();
 					}
 				}, '∗')