yText delta attributes is not correct when undo

[caifenglei]

Describe the bug
yText delta attributes are not correct when undo.

To Reproduce
Steps to reproduce the behavior:

1. ClientA: insert text S and AAAAA
2. ClientB: insert BBB in AAAAA
3. ClientA: undo
4. BBB's attribute is using S's, but not its origin value

Expected behavior
BBB's attribute is its origin set value

Screenshots

Environment Information

• Yjs version 13.6.14

Additional context
vue demo code:

    // Client A
    const ydoc = new Y.Doc()
    const ymap = ydoc.getMap("root")
    const contentText = new Y.Text()
    const propertyMap = new Y.Map()
    ymap.set('docContent', contentText)
    ymap.set('propertyMap', propertyMap)
    const undoManager = new Y.UndoManager(ymap, {trackedOrigins: new Set(['trackUndo'])})
    ymap.observeDeep((events: Y.YEvent<any>[], transaction: Y.Transaction) => {
      console.info(events, 'events A>>>>>>>>>>>>')
    })

    ydoc.transact(() => {
      contentText.insert(0, 'S', {type: 'MK_E_9', id: 'C_000'})
    }, 'trackUndo')

    undoManager.stopCapturing()
    ydoc.transact(() => {
      contentText.insert(1, 'AAAAA', {type: '10', id: 'C_001'})
      previewText('ClientA insert S and AAAAA', contentText)
    }, 'trackUndo')

    //Client B
    const ydocRemote = new Y.Doc()
    syncA2B(ydoc, ydocRemote)
    
    const ymapRemote = ydocRemote.getMap("root")
    const propertyMapB = ymapRemote.get('propertyMap') as Y.Map<any>
    const contentTextB = ymapRemote.get('docContent') as Y.Text

    contentTextB.insert(3, 'BBB', {type: '10', id: 'C_003'})
    syncB2A(ydocRemote, ydoc)
    previewText('ClientB insert BBB in AAAAA', contentText)

    //Client A
    undoManager.undo()
    previewText('ClientA undo', contentText)


    function syncA2B(ydocA, ydocB) {
    Y.applyUpdate(ydocB, Y.encodeStateAsUpdate(ydocA))
  }

  function syncB2A(ydocB, ydocA) {
    Y.applyUpdate(ydocA, Y.encodeStateAsUpdate(ydocB))
  }

  function previewText(desc:string, yText: Y.Text) {
    previewTexts.value.push({delta: yText.toDelta(), content: yText.toString(), desc: desc})
  }