devtools: Allow highlighting elements from the inspector (#35822)

This change connects the `HighlighterActor` from the devtools with the
document, which will draw a blue rectangle over any highlighted dom
node.



https://github.com/user-attachments/assets/571b2dab-497f-4102-9e55-517cdcc040ba




---
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- [X] `./mach build -d` does not report any errors
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- [X] These changes do not require tests because we don't have devtools
tests

Signed-off-by: Simon Wülker <simon.wuelker@arcor.de>

components/script/script_thread.rs

@@ -2069,6 +2069,9 @@ impl ScriptThread {
                     None => warn!("Message sent to closed pipeline {}.", id),
                 }
             },
+            DevtoolScriptControlMsg::HighlightDomNode(id, node_id) => {
+                devtools::handle_highlight_dom_node(&documents, id, node_id)
+            },
         }
     }