Fix merge error logging order (#58310)

Fix merge error order

Author: Georgehe4

pandas/core/reshape/merge.py

@@ -2065,8 +2065,8 @@ def _validate_left_right_on(self, left_on, right_on):
  or is_string_dtype(ro_dtype)
  ):
  raise MergeError(
- f"Incompatible merge dtype, {ro_dtype!r} and "
- f"{lo_dtype!r}, both sides must have numeric dtype"
+ f"Incompatible merge dtype, {lo_dtype!r} and "
+ f"{ro_dtype!r}, both sides must have numeric dtype"
  )
 
  # add 'by' to our key-list so we can have it in the