metal: prepare for objc2 frameworks v0.3

These will have a bunch of default features enabled, so let's
pre-emptively disable them.

blade-graphics/Cargo.toml

@@ -21,8 +21,12 @@ raw-window-handle = "0.6"
 
 [target.'cfg(any(target_os = "ios", target_os = "macos"))'.dependencies]
 objc2 = "0.5"
-objc2-foundation = { version = "0.2", features = ["NSArray"] }
-objc2-metal = { version = "0.2", features = [
+objc2-foundation = { version = "0.2", default-features = false, features = [
+    "std",
+    "NSArray",
+] }
+objc2-metal = { version = "0.2", default-features = false, features = [
+    "std",
     "MTLTypes",
     "MTLPixelFormat",
     "MTLResource",
@@ -55,23 +59,26 @@ objc2-metal = { version = "0.2", features = [
     "MTLCaptureScope",
     "block2",
 ] }
-objc2-quartz-core = { version = "0.2", features = [
+objc2-quartz-core = { version = "0.2", default-features = false, features = [
+    "std",
     "objc2-metal",
     "CALayer",
     "CAMetalLayer",
 ] }
 naga = { workspace = true, features = ["msl-out"] }
 
 [target.'cfg(target_os = "macos")'.dependencies]
-objc2-app-kit = { version = "0.2", features = [
+objc2-app-kit = { version = "0.2", default-features = false, features = [
+    "std",
     "objc2-quartz-core",
     "NSResponder",
     "NSView",
     "NSWindow",
 ] }
 
 [target.'cfg(target_os = "ios")'.dependencies]
-objc2-ui-kit = { version = "0.2", features = [
+objc2-ui-kit = { version = "0.2", default-features = false, features = [
+    "std",
     "objc2-quartz-core",
     "UIResponder",
     "UIView",