manager: if manager incompatible with current kernel, don't save ksud (#2895)

I think we should'nt install kernelsu's userspace when manager
incompatible with current kernel
this maybe cause a lot of bug, for example, when user install 2.x
kernelsu manager, but not update
his kernel to 2.x, ksud will return "kernel version 0", because ksud
incompatible with old supercall impl

manager/app/src/main/java/com/sukisu/ultra/ui/MainActivity.kt

@@ -75,7 +75,7 @@ class MainActivity : ComponentActivity() {
             super.onCreate(savedInstanceState)
 
             val isManager = Natives.isManager
-            if (isManager) {
+            if (isManager && !Natives.requireNewKernel()) {
                 install()
             }
 

manager/app/src/main/java/com/sukisu/ultra/ui/util/KsuCli.kt

@@ -322,6 +322,11 @@ fun installBoot(
 
     // if boot uri is empty, it is direct install, when success, we should show reboot button
     onFinish(bootUri == null && result.isSuccess, result.code)
+
+    if (bootUri == null && result.isSuccess) {
+        install()
+    }
+
     return result.isSuccess
 }