manifest: Update nrf hw models to latest

* Update the HW models module to
a715dcc179f1a71f51c574165958b72fe932ae3f

Including the following:
* a715dcc irq_ctrl: Fix interrupt name getter
* b9e1f00 Makefile: For 5340 build both HAL versions as separate libraries
* 68aa50b Makefile: Set default target to compile and fix makefiles rules
* 0cf5ea9 nrfx_glue: Provide a stubbed NRFX_DELAY for builds without Zephyr
* b0d95c2 doc: Update required Nordic nrfx version to 3.2

Signed-off-by: Alberto Escolar Piedras <alberto.escolar.piedras@nordicsemi.no>