handle prepended 'xpath=' (#552)

* handle prepended 'xpath='

* changeset

Author: seanmcguire12

.changeset/healthy-walls-refuse.md

@@ -0,0 +1,5 @@
+---
+"@browserbasehq/stagehand": patch
+---
+
+accept xpaths with 'xpath=' prepended to the front in addition to xpaths without

lib/handlers/extractHandler.ts

@@ -184,7 +184,7 @@ export class StagehandExtractHandler {
     await this.stagehandPage._waitForSettledDom(domSettleTimeoutMs);
     await this.stagehandPage.startDomDebug();
 
-    const targetXpath = selector;
+    const targetXpath = selector?.replace(/^xpath=/, "") ?? "";
 
     // **2:** Store the original DOM before any mutations
     // we need to store the original DOM here because calling createTextBoundingBoxes()