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/shared/devtools/lib.rs

@@ -273,6 +273,8 @@ pub enum DevtoolScriptControlMsg {
     GetCssDatabase(IpcSender<HashMap<String, CssDatabaseProperty>>),
     /// Simulates a light or dark color scheme for the given pipeline
     SimulateColorScheme(PipelineId, Theme),
+    /// Highlight the given DOM node
+    HighlightDomNode(PipelineId, Option<String>),
 }
 
 #[derive(Clone, Debug, Deserialize, Serialize)]