Change Context::storage() return type to ContextStorageInterface

`ExecutionContextAwareInterface` should not be relevant for end-users / it was mainly exposed for the FFI fiber handler; calling any of its method with enabled fiber handler would have broken the storage.
Swoole context storage README creates a new storage instead of wrapping `Context::storage()`: `Context::setStorage(new SwooleContextStorage(new ContextStorage()));`.

src/Context/Context.php

@@ -16,7 +16,7 @@ final class Context implements ContextInterface
 {
     private const OTEL_PHP_DEBUG_SCOPES_DISABLED = 'OTEL_PHP_DEBUG_SCOPES_DISABLED';
 
-    private static ContextStorageInterface&ExecutionContextAwareInterface $storage;
+    private static ContextStorageInterface $storage;
 
     // Optimization for spans to avoid copying the context array.
     private static ContextKeyInterface $spanContextKey;
@@ -36,12 +36,12 @@ public static function createKey(string $key): ContextKeyInterface
         return new ContextKey($key);
     }
 
-    public static function setStorage(ContextStorageInterface&ExecutionContextAwareInterface $storage): void
+    public static function setStorage(ContextStorageInterface $storage): void
     {
         self::$storage = $storage;
     }
 
-    public static function storage(): ContextStorageInterface&ExecutionContextAwareInterface
+    public static function storage(): ContextStorageInterface
     {
         /** @psalm-suppress RedundantPropertyInitializationCheck */
         return self::$storage ??= new FiberBoundContextStorage();

src/Context/FiberBoundContextStorage.php

@@ -15,10 +15,8 @@
 /**
  * @internal
  */
-final class FiberBoundContextStorage implements ContextStorageInterface, ContextStorageHeadAware, ExecutionContextAwareInterface
+final class FiberBoundContextStorage implements ContextStorageInterface, ContextStorageHeadAware
 {
-    use ExecutionContextAwareNotSupported;
-
     /** @var WeakMap<object, ContextStorageHead> */
     private WeakMap $heads;