If you want to apply conditional validation on 'Aadhar Card' then you need to add 'Image Type' input as 'IdentityCard'.
{{userInfoFormGroup.controls.aadharCard.errors.image.message}}
If you want to apply conditional validation on 'Document File' then you need to add 'File Type' input as 'IdentityCard'.
{{userInfoFormGroup.controls.panCard.errors.image.message}}