Remove unneccessary _FileManagerImpl.delegate (#801)

Author: jmschonfeld

Sources/FoundationEssentials/FileManager/FileManager+Basics.swift

@@ -41,7 +41,6 @@ extension LARGE_INTEGER /* : @retroactive Equatable */ {
 
 internal struct _FileManagerImpl {
     weak var _manager: FileManager?
-    weak var delegate: FileManagerDelegate?
 
     var fileManager: FileManager {
         guard let _manager else {
@@ -50,14 +49,6 @@ internal struct _FileManagerImpl {
         return _manager
     }
 
-    var safeDelegate: FileManagerDelegate? {
-#if FOUNDATION_FRAMEWORK
-        fileManager._safeDelegate() as? FileManagerDelegate
-#else
-        self.delegate
-#endif
-    }
-    
     init() {}
 
     #if FOUNDATION_FRAMEWORK