patch stagehand agent api support (#1116)

# why

currently when using stagehand agent through api, it returns early
without executing

# what changed

we now properly handle the options when none are present 

# test plan
tested locally, and tested across other cua agents to ensure no breaking
changes

Author: tkattkat

.changeset/nice-dogs-march.md

@@ -0,0 +1,5 @@
+---
+"@browserbasehq/stagehand": patch
+---
+
+patch stagehand agent api support

lib/index.ts

@@ -992,6 +992,9 @@ export class Stagehand {
             throw new StagehandNotInitializedError("API client");
           }
 
+          if (!options) {
+            options = {};
+          }
           if (!options.options) {
             options.options = {};
           }