Cracked grout and leak in shower side wall - short and long-term fix given foundation work?
A short term solution is to build a water tight covering over the wall (assuming the shower pan is functioning).
An example (functional and ugly) is to glue FRP Wall Board ,connectors and caulk.

cut FRP Wall Board to size
glue FRP Wall Board with caulk to existing wall
caulk all joints generously


when redoing the ledge add a greater slope towards the shower