Apple M1: Removed unavailable CPU core dialog box

Removed the unavailable CPU core dialog box that asked users to change their
selected CPU core to one that is available. Instead, Dolphin now just overrides
the core to the default, and logs that it performed the override.

Source/Core/Core/PowerPC/JitInterface.cpp

@@ -71,9 +71,8 @@ CPUCoreBase* InitJitCore(PowerPC::CPUCore core)
     break;
 
   default:
-    PanicAlertFmtT("The selected CPU emulation core ({0}) is not available. "
-                   "Please select a different CPU emulation core in the settings.",
-                   core);
+    // Under this case the caller overrides the CPU core to the default and logs that
+    // it performed the override.
     g_jit = nullptr;
     return nullptr;
   }