BUG: handle empty prefix in pyarrow-backed removeprefix

Author: vkverma9534

pandas/core/arrays/_arrow_string_mixins.py

@@ -203,6 +203,8 @@ def _str_swapcase(self) -> Self:
         return self._from_pyarrow_array(pc.utf8_swapcase(self._pa_array))
 
     def _str_removeprefix(self, prefix: str):
+        if prefix == "":
+            return self
         starts_with = pc.starts_with(self._pa_array, pattern=prefix)
         removed = pc.utf8_slice_codeunits(self._pa_array, len(prefix))
         result = pc.if_else(starts_with, removed, self._pa_array)