Should one re-perform the Dhuhr prayer if, during the Friday sermon, one doubts the cleanliness and purity of one's clothes, knowing that one suffers from intermittent urinary incontinence?

You must avoid intrusive thoughts (waswas) and not pay them any attention. If you doubt whether something came out of you or not, the default is the validity of your purity (tahara) and that no urine came out. Therefore, you are not required to repeat the prayer. It is obligatory for anyone from whom drops of urine exit to wait until it stops, then perform ablution (wudu') and pray, and remove any impurity from their body and clothes.