iOS: Hide the status bar when immersive mode is enabled

prefersStatusBarHidden was dead code - it computed an orientation and a
(commented out) user preference, then unconditionally returned false. So the
status bar was only ever hidden on iPhone in landscape, and only because iOS
does that on its own in compact height.

Now it honors bImmersiveMode from the DisplayLayoutConfig matching the current
orientation, so it also applies in portrait and on iPad. Adds the corresponding
checkbox to the iOS system settings, and updates the status bar on rotation and
when the setting is toggled.

Also fixes a missing break in the ROTATE_UPDATED case in System_Notify, and a
static/non-static mismatch on sceKernelLoadModuleBufferUsbWlan that broke the
build (the header intentionally exposes it for sceVshBridge).

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JZk5y4Fzw811WJoNWZb8Sc

Core/HLE/sceKernelModule.cpp

@@ -2539,7 +2539,7 @@ static u32 sceKernelLoadModuleDNAS(const char *name, u32 flags)
 }
 
 // Pretty sure this is a badly brute-forced function name...
-static SceUID sceKernelLoadModuleBufferUsbWlan(u32 size, u32 bufPtr, u32 flags, u32 lmoptionPtr)
+SceUID sceKernelLoadModuleBufferUsbWlan(u32 size, u32 bufPtr, u32 flags, u32 lmoptionPtr)
 {
 	if (flags != 0) {
 		WARN_LOG_REPORT(Log::Loader, "sceKernelLoadModuleBufferUsbWlan: unsupported flags: %08x", flags);