chore: add an error handling in _adjust_image_payload (#1172)

* refact: _adjust_image_payload

* style: move import binascii

* refactor: raise helpful ValueError on UnicodeDecodeError

* refactor: add from e

* style: ruff formatting

Author: wooyoung294

appium/webdriver/extensions/images_comparison.py

@@ -147,4 +147,7 @@ def _add_commands(self) -> None:
 
 
 def _adjust_image_payload(payload: Base64Payload) -> str:
-    return payload if isinstance(payload, str) else payload.decode('utf-8')
+    try:
+        return payload if isinstance(payload, str) else payload.decode('utf-8')
+    except UnicodeDecodeError as e:
+        raise ValueError('The image payload cannot be serialized to a string. Make sure to base64-encode it first') from e