Merge pull request swiftlang#74520 from slavapestov/fix-failure-type-witness-6.0

[6.0] Concurrency: Fix default type witness for AsyncSequence.Failure

Author: slavapestov

stdlib/public/Concurrency/AsyncSequence.swift

@@ -81,7 +81,7 @@ public protocol AsyncSequence<Element, Failure> {
 
   /// The type of errors produced when iteration over the sequence fails.
   @available(SwiftStdlib 6.0, *)
-  associatedtype Failure: Error = AsyncIterator.Failure
+  associatedtype Failure: Error = any Error
       where AsyncIterator.Failure == Failure
 
   /// Creates the asynchronous iterator that produces elements of this