To what extent is the hadith "If you see a man frequenting the mosques, then bear witness to his faith" authentic?

The hadith: "If you see a man frequenting the mosque, testify to his faith (Iman)" has a weak chain of narration due to Darraj ibn Sum'an Abu al-Samh, whom the imams deemed weak in his narrations from Abu al-Haytham. Ibn Rajab also pointed out that its text (matn) is objectionable (munkar) because it testifies to faith (Iman), which is an inner state not discernible by a human being. Rather, one testifies to Islam, as it is an outward description, citing the hadith of Sa'd ibn Abi Waqqas with the Prophet, peace and blessings be upon him.