I don't see any internal routing for measuring VDD. However, there is internal VBACKUP monitoring. If VDD and VBACKUP connected together in cusotmer's design, I believe the VDD can be measured through VBACKUP.
Can this meet your requirement?
VBACKUP is a separate pin on the module and can likely be tied together with VDD. What is the procedure for monitoring VBACKUP and getting an accurate voltage reading in PSoC 6?
Attched a simple demo project demontrating the internal routing for VBACKUP monitoring.
It just includes a ADC and UART block. The VABCKUP voltage is printed through UART in mV.