[webdriver] Move Webdriver to ServoShell (#36714)

Moving `webdriver` to `servoshell`:

- Let `servoshell` manage lifecycle of `webdriver`
- One by one, move the handling of webdriver commands from
`constellation` to `embedder`

Partially fix: https://github.com/servo/servo/issues/37370
Partially fix webdriver test timeout with `no_top_browsing_context`

cc: @xiaochengh

---------

Signed-off-by: batu_hoang <longvatrong111@gmail.com>

components/constellation/tracing.rs

@@ -247,6 +247,7 @@ mod from_script {
                 Self::FinishJavaScriptEvaluation(..) => {
                     target_variant!("FinishJavaScriptEvaluation")
                 },
+                Self::WebDriverCommand(..) => target_variant!("WebDriverCommand"),
             }
         }
     }