iOS: Disable the sandbox for the cargo build script by default

When the xcode project is in a sub-dir but the cargo build tries to access a file outside, this won't work.

cspell.json

@@ -151,6 +151,7 @@
         "rustdocs",
         "rustflags",
         "rvalue",
+        "SANDBOXING",
         "scrollview",
         "SDK",
         "seti",

demos/energy-monitor/ios-project.yml

@@ -3,6 +3,8 @@
 name: Energy Monitor
 options:
   bundleIdPrefix: dev.slint.demos
+settings:
+  ENABLE_USER_SCRIPT_SANDBOXING: NO
 targets:
   Energy Monitor:
     type: application

demos/home-automation/rust/ios-project.yml

@@ -3,6 +3,8 @@
 name: Home Automation
 options:
   bundleIdPrefix: dev.slint.demos
+settings:
+  ENABLE_USER_SCRIPT_SANDBOXING: NO
 targets:
   Home Automation:
     type: application

docs/astro/src/content/docs/guide/platforms/ios.mdx

@@ -45,6 +45,8 @@ cargo build --target=aarch64-apple-ios
 name: My App
 options:
   bundleIdPrefix: com.company
+settings:
+  ENABLE_USER_SCRIPT_SANDBOXING: NO
 targets:
   MyApp:
     type: application