devtools: Replace new with register for NodeActor (#44071)

Added a `register` method to `NodeActor` following the same pattern used
by other actors in the devtools codebase. Updated
`NodeInfoToProtocol::get_or_register_node_actor` to use it instead of
constructing `NodeActor` directly.
Testing: 
Ran `./mach try linux-unit-tests` and `./mach test-devtools`. No new
failures introduced.

Fixes:part of  #43800

---------

Signed-off-by: Emmanuel Paul Elom <elomemmanuel007@gmail.com>

components/devtools/actors/inspector/node.rs

@@ -258,6 +258,30 @@ impl Actor for NodeActor {
     }
 }
 
+impl NodeActor {
+    pub fn register(
+        registry: &ActorRegistry,
+        script_id: String,
+        script_chan: GenericSender<DevtoolScriptControlMsg>,
+        pipeline: PipelineId,
+        walker: String,
+    ) -> String {
+        let name = registry.new_name::<Self>();
+
+        registry.register_script_actor(script_id, name.clone());
+
+        let actor = Self {
+            name: name.clone(),
+            script_chan,
+            pipeline,
+            walker,
+            style_rules: AtomicRefCell::new(HashMap::new()),
+        };
+
+        registry.register(actor);
+        name
+    }
+}
 pub trait NodeInfoToProtocol {
     fn encode(
         self,
@@ -278,18 +302,13 @@ impl NodeInfoToProtocol for NodeInfo {
     ) -> NodeActorMsg {
         let get_or_register_node_actor = |id: &str| {
             if !registry.script_actor_registered(id.to_string()) {
-                let node_name = registry.new_name::<NodeActor>();
-                registry.register_script_actor(id.to_string(), node_name.clone());
-
-                let node_actor = NodeActor {
-                    name: node_name.clone(),
-                    script_chan: script_chan.clone(),
+                NodeActor::register(
+                    registry,
+                    id.to_string(),
+                    script_chan.clone(),
                     pipeline,
-                    walker: walker.clone(),
-                    style_rules: AtomicRefCell::new(HashMap::new()),
-                };
-                registry.register(node_actor);
-                node_name
+                    walker.clone(),
+                )
             } else {
                 registry.script_to_actor(id.to_string())
             }