Enable arm64e architecture slice for iOS devices

[sewerynplazuk]

Hey! I was looking through scripts/build.sh and noticed that the arm64e build is currently commented out with the following note:

# The World is not ready for arm64e!
# build "arm64e" "iPhoneOS" ${TMP_BUILD_DIR} "iphoneos"

I'd like to argue that the world is actually ready! 😅 With the current state of Apple's enhanced security features, Pointer Authentication Codes (PAC) are the standard on modern iPhones. To enable PAC and fully utilize these hardware-level security enhancements, Apple requires all app dependencies to include the arm64e architecture slice.

Currently, because the OpenSSL XCFramework is missing this slice, it acts as a blocker for downstream projects trying to adopt full PAC security on iOS. Therefore we should uncomment the arm64e build steps in scripts/build.sh and ensure that the resulting OpenSSL.xcframework packages this slice for iPhoneOS.

[krzyzanowskim]

I'd like to verify whether AppStore accepts such binary. It was rejected in the past.