use css selector instead of xpath (#551)

skyvern/exceptions.py

@@ -47,17 +47,17 @@ class ScriptNotFound(SkyvernException):
 
 
 class MissingElement(SkyvernException):
-    def __init__(self, xpath: str | None = None, element_id: str | None = None):
+    def __init__(self, selector: str | None = None, element_id: str | None = None):
         super().__init__(
             f"Found no elements. Might be due to previous actions which removed this element."
-            f" xpath={xpath} element_id={element_id}",
+            f" selector={selector} element_id={element_id}",
         )
 
 
 class MultipleElementsFound(SkyvernException):
-    def __init__(self, num: int, xpath: str | None = None, element_id: str | None = None):
+    def __init__(self, num: int, selector: str | None = None, element_id: str | None = None):
         super().__init__(
-            f"Found {num} elements. Expected 1. num_elements={num} xpath={xpath} element_id={element_id}",
+            f"Found {num} elements. Expected 1. num_elements={num} selector={selector} element_id={element_id}",
         )
 
 
@@ -318,6 +318,11 @@ class MissingElementInIframe(SkyvernException):
         super().__init__(f"Found no iframe includes the element. element_id={element_id}")
 
 
+class MissingElementInCSSMap(SkyvernException):
+    def __init__(self, element_id: str) -> None:
+        super().__init__(f"Found no css selector in the CSS map for the element. element_id={element_id}")
+
+
 class InputActionOnSelect2Dropdown(SkyvernException):
     def __init__(self, element_id: str):
         super().__init__(