Fix crash when creating documents in an opened folder on android (#18651)

* fix crash when creating documents in an opened folder

* fix crash on folder delete on android

Author: emmauss

src/Android/Avalonia.Android/Platform/Storage/AndroidStorageItem.cs

@@ -159,7 +159,8 @@ public AndroidStorageFolder(Activity activity, AndroidUri uri, bool needsExterna
     public Task<IStorageFile?> CreateFileAsync(string name)
     {
         var mimeType = MimeTypeMap.Singleton?.GetMimeTypeFromExtension(MimeTypeMap.GetFileExtensionFromUrl(name)) ?? "application/octet-stream";
-        var newFile = DocumentsContract.CreateDocument(Activity.ContentResolver!, Uri, mimeType, name);
+        var treeUri = DocumentsContract.BuildDocumentUriUsingTree(Uri, DocumentsContract.GetTreeDocumentId(Uri));
+        var newFile = DocumentsContract.CreateDocument(Activity.ContentResolver!, treeUri!, mimeType, name);
         if(newFile == null)
         {
             return Task.FromResult<IStorageFile?>(null);
@@ -170,7 +171,8 @@ public AndroidStorageFolder(Activity activity, AndroidUri uri, bool needsExterna
 
     public Task<IStorageFolder?> CreateFolderAsync(string name)
     {
-        var newFolder = DocumentsContract.CreateDocument(Activity.ContentResolver!, Uri, DocumentsContract.Document.MimeTypeDir, name);
+        var treeUri = DocumentsContract.BuildDocumentUriUsingTree(Uri, DocumentsContract.GetTreeDocumentId(Uri));
+        var newFolder = DocumentsContract.CreateDocument(Activity.ContentResolver!, treeUri!, DocumentsContract.Document.MimeTypeDir, name);
         if (newFolder == null)
         {
             return Task.FromResult<IStorageFolder?>(null);
@@ -205,7 +207,8 @@ async Task DeleteContents(AndroidStorageFolder storageFolder)
                 }
             }
 
-            DocumentsContract.DeleteDocument(Activity.ContentResolver!, storageFolder.Uri);
+            var treeUri = DocumentsContract.BuildDocumentUriUsingTree(storageFolder.Uri, DocumentsContract.GetTreeDocumentId(storageFolder.Uri));
+            DocumentsContract.DeleteDocument(Activity.ContentResolver!, treeUri!);
         }
     }