`incoming` handler runs twice when using `.bulkDocs()`

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Since PouchDB 6.0.3, the incoming handler runs twice when using the .bulkDocs method. You can demostrate this issue with this snippet:

const PouchDB = require('pouchdb')
PouchDB.plugin(require('transform-pouch'))

const db = new PouchDB('.test')
let i = 0
db.transform({
  incoming: function (doc) {
    i++
    return doc
  }
})

Promise.resolve().then(async () => {
  await db.bulkDocs([{ _id: 'a' }])
  console.log(i === 2)
}).catch((err) => {
  console.error(err)
}).then(db.destroy)