I would ask you to consider: what would you actually gain by forcing priests to report? I think it would only do harm, not good.
If you make priests mandatory reporters, they will start each confession with a disclaimer informing congregants that they are a mandatory reporter. In that case, no molester will confess their crimes to their priest. And at least now, there is some nonzero chance the priest can get the molester to turn themselves in. If the molester is confessing their crimes, they're obviously religious. At least then the priest can tell the molester, "if you do not turn yourself in, you will go to Hell." I don't know how effective that will be, but it results in at least a non-zero number of molesters turning themselves in.
And then you have to consider the harm done to the priest. You're putting someone in a position where the law requires them to do a thing that they literally believe will subject them to eternal damnation. You can lock up a priest for decades until they testify, but all you'll really accomplish is the imprisonment of a nonviolent person who has no intention of ever harming anyone.
At some point this just feels like an exercise in abusing the mentally ill. Imagine if there was a schizophrenic that truly believed that if they testified about a crime they witnessed, that for whatever bizarre reason, they would instantly spontaneously combust. From their perspective, that poor soul would face the impossible choice of either sitting in a prison cell forever or dying a horrible fiery death. I would say it's deeply immoral to put a person like that in that condition. You're basically locking someone up for the crime of being mentally ill.