Remove @available annotations from HKDF functions that are no longer needed

Co-authored-by: jkoritzinsky <1571408+jkoritzinsky@users.noreply.github.com>

Author: Copilot

src/native/libs/System.Security.Cryptography.Native.Apple/pal_swiftbindings.swift

@@ -202,7 +202,6 @@ enum HKDFError: Error {
 }
 
 @_silgen_name("AppleCryptoNative_HKDFExpand")
-@available(macOS 14, iOS 14, tvOS 14, *)
 public func AppleCryptoNative_HKDFExpand(
     hashAlgorithm: Int32,
     prkPtr: UnsafeMutableRawPointer,
@@ -248,7 +247,6 @@ public func AppleCryptoNative_HKDFExpand(
 }
 
 @_silgen_name("AppleCryptoNative_HKDFExtract")
-@available(macOS 14, iOS 14, tvOS 14, *)
 public func AppleCryptoNative_HKDFExtract(
     hashAlgorithm: Int32,
     ikmPtr: UnsafeMutableRawPointer,
@@ -295,7 +293,6 @@ public func AppleCryptoNative_HKDFExtract(
 }
 
 @_silgen_name("AppleCryptoNative_HKDFDeriveKey")
-@available(macOS 14, iOS 14, tvOS 14, *)
 public func AppleCryptoNative_HKDFDeriveKey(
     hashAlgorithm: Int32,
     ikmPtr: UnsafeMutableRawPointer,