Is the narration of Ibn Abbas regarding moving the finger in prayer and his saying, "That is sincerity," authentic (sahih) or good (hasan)?

The narration mentioned on the authority of Ibn Abbas regarding moving the finger in prayer and that it is "sincerity" was reported by Abd al-Razzaq and Ibn Abi Shaybah, but its chain of transmission is weak due to two defects: the ananah (reporting with "on the authority of") of Abu Ishaq al-Sabii, who was a mudallis (one who practices tadlis in narration) and confused, and the obscurity of his شيخ (shaykh/teacher), al-Tamimi, from whom no one reported but Abu Ishaq.