Fix notifications entry layout

[jreiberkyle]

Related Issue(s):

Closes #916

Proposed Changes:

For inclusion in changelog (if applicable):

1. Fix order request notification entry layout.

Not intended for changelog:

Diff of User Interface

Script:

import json

from planet import order_request

notification = True
order_uuid = 'test_order'
products = [
        order_request.product(['20230412_054952_10_24cc'], item_type='psscene', product_bundle='analytic_udm2')]
tools = None

if notification:
    notifications = order_request.notifications(
        webhook_per_order=True,
        webhook_url="http://webhookurl",
        email=False,
    )

request = order_request.build_request(
    order_uuid,
    products=products,
    tools=tools,
    notifications=notifications if notifications else None,
)

print(json.dumps(request))

Old behavior:

notifications entry is incorrect:

{
  "name": "test_order",
  "products": [
    {
      "item_ids": [
        "20230412_054952_10_24cc"
      ],
      "item_type": "PSScene",
      "product_bundle": "analytic_udm2"
    }
  ],
  "notifications": {
    "webhook_url": "http://webhookurl",
    "webhook_per_order": true
  }
}

New behavior:

notifications entry is corrected:

{
  "name": "test_order",
  "products": [
    {
      "item_ids": [
        "20230412_054952_10_24cc"
      ],
      "item_type": "PSScene",
      "product_bundle": "analytic_udm2"
    }
  ],
  "notifications": {
    "webhook": {
      "url": "http://webhookurl",
      "per_order": true
    },
    "email": false
  }
}

PR Checklist:

• [] This PR is as small and focused as possible
• [] If this PR includes proposed changes for inclusion in the changelog, the title of this PR summarizes those changes and is ready for inclusion in the Changelog.
• [] I have updated docstrings for function changes and docs in the 'docs' folder for user interface / behavior changes
• [] This PR does not break any examples or I have updated them

(Optional) @mentions for Notifications:

[kevinlacaille]

Looks great! Great catch, @julianblue!