fix: use iOS OTP target for visionOS builds

OTP's config.sub doesn't recognize xros yet. Using iOS target
(aarch64-apple-ios) works since the actual SDK flags still target
the visionOS platform via xcrun -sdk xros.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: Adrian Ibañez

.github/config/apple-platforms.json

@@ -65,7 +65,7 @@
       "base_arch": "xros",
       "openssl_prefix": "_build/ios-openssl/build/openssl.xros",
       "openssl_arch": "xros-xcrun",
-      "otp_arch": "aarch64-apple-xros",
+      "otp_arch": "aarch64-apple-ios",
       "rust_target": "aarch64-apple-visionos"
     },
     {
@@ -76,7 +76,7 @@
       "base_arch": "xrossim",
       "openssl_prefix": "_build/ios-openssl/build/openssl.xrossim.arm64",
       "openssl_arch": "xrossimulator-xcrun",
-      "otp_arch": "aarch64-apple-xrossimulator",
+      "otp_arch": "aarch64-apple-iossimulator",
       "rust_target": "aarch64-apple-visionos-sim"
     }
   ]