Update documents with fields with strings array leads to changes type: SS->LIST

[komanton]

Describe the bug A clear and concise description of what the bug is.

To Reproduce Steps to reproduce the behavior:

1. View document { "username": "[email protected]", "grps": [ "group-id-1", "group-id-2" ] }
2. Press Save button
3. Get document with dynamoose where scheme looks like this:

const schema = new Schema({
  username: {
    type: String,
    hashKey: true
  },
 grps: {
    type: [String],
    default: []
  }
});

export default dynamoose.model<SomeInterfaceSchema, unknown>("Name", schema );

Dynamoose will fail because type of "grps" is changed from SS to LIST

Expected: step 2 should not change the type of "grps" to LIST

Expected behavior A clear and concise description of what you expected to happen.

Screenshots If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: Windows
• Browser chrome
• Version [e.g. 22]

Additional context Add any other context about the problem here