Improve trusted-click-element scriptlet

Use `openOrClosedShadowRoot` to lookup shadow root.

Related issue:
AdguardTeam/AdguardFilters#178995

assets/resources/scriptlets.js

@@ -4482,14 +4482,28 @@ function trustedClickElement(
         }
     }
 
+    const getShadowRoot = elem => {
+        // Firefox
+        if ( elem.openOrClosedShadowRoot ) {
+            return elem.openOrClosedShadowRoot;
+        }
+        // Chromium
+        if ( typeof chrome === 'object' ) {
+            if ( chrome.dom && chrome.dom.openOrClosedShadowRoot ) {
+                return chrome.dom.openOrClosedShadowRoot(elem);
+            }
+        }
+        return null;
+    };
+
     const querySelectorEx = (selector, context = document) => {
         const pos = selector.indexOf(' >>> ');
         if ( pos === -1 ) { return context.querySelector(selector); }
         const outside = selector.slice(0, pos).trim();
         const inside = selector.slice(pos + 5).trim();
         const elem = context.querySelector(outside);
         if ( elem === null ) { return null; }
-        const shadowRoot = elem.shadowRoot;
+        const shadowRoot = getShadowRoot(elem);
         return shadowRoot && querySelectorEx(inside, shadowRoot);
     };