changed clearHelperText() to set local variable helperText to empty string and then call hideHelperText()
private method hideHelperText() contains the code from the previous clearHelperText method and is called instead of clearHelperText() from setErrorText() and setSuccessText()
This ensures that helperText will be reinstated when error or success text is removed (eg after successful validation) unless it has been cleared
changed clearHelperText() to set local variable helperText to empty string and then call hideHelperText() private method hideHelperText() contains the code from the previous clearHelperText method and is called instead of clearHelperText() from setErrorText() and setSuccessText()
This ensures that helperText will be reinstated when error or success text is removed (eg after successful validation) unless it has been cleared