الجواب حامدا و مصلیا
It is Sunna, and also part of the completion of the prayer, for the worships to stand close to each other during the congregational prayer. The Holy Prophet used to encourage people to do this. He also warned about leaving spaces between the lines during Salah. For this reason, if is it possible to stand together during Salah while observing precautionary measures, then the way of the Sunna should not be left off. However, precautionary measures cannot be observed and the spread of Covid is possible if the worshipers stand together, then hopefully there will be so sin in standing with some distance between one and other to observe precautionary measures, and Salah in this condition will also be valid.