Saani, I had the same issue, so I can tell your clearly, once you submit your PR application and receive the AoR, if your IELTS expires after that no issues at all...
but for example you will receive your IELTS say next Wednesday, will you be in a position to submit your application before the IELTS expiry ?
If you cannot submit then apply for the IELTS test immediately and it will take a few days to get your results, once you get your score and you have same points or above the cut off then proceed with the ITA else if you score low then, decline the ITA and come back to the pool