Instances page shows error after the second click on 'Confirm Resize' button.

[Olga Klochkova]

Precondition
At least one Instance, few available flavors

Steps to reproduce:
1. Login to Horizon Dashboard as admin user
2. Navigate to Project -> Instances
3. Click dropdown menu with instance actions and choose "resize instance"
4. Enter valid settings in the dialog box. Click 'Resize' button.
5. Wait until request to Confirm Resize/Migrate appears in the instances table.
6. Click 'Confirm Resize' button

Confirm resize' button locks up until the process finishes. 'Confirm' button unlocks after some time after process is finished. While its name is not changed back to 'create snapshot' it can be clicked by user.
An unexpected error has occurred. Try refreshing the page. If that doesn't help, contact your local administrator."
In this case the following error appears: "Something went wrong!

Expected result:
Once the button unlocks and is clickable, the operation should succeed.

VERSION:
  feature_groups:
    - mirantis
  production: "docker"
  release: "8.0"
  api: "1.0"
  build_number: "569"
  build_id: "569"
  fuel-nailgun_sha: "558ca91a854cf29e395940c232911ffb851899c1"
  python-fuelclient_sha: "4f234669cfe88a9406f4e438b1e1f74f1ef484a5"
  fuel-agent_sha: "658be72c4b42d3e1436b86ac4567ab914bfb451b"
  fuel-nailgun-agent_sha: "b2bb466fd5bd92da614cdbd819d6999c510ebfb1"
  astute_sha: "b81577a5b7857c4be8748492bae1dec2fa89b446"
  fuel-library_sha: "33634ec27be77ecfb0b56b7e07497ad86d1fdcd3"
  fuel-ostf_sha: "3bc76a63a9e7d195ff34eadc29552f4235fa6c52"
  fuel-mirror_sha: "fb45b80d7bee5899d931f926e5c9512e2b442749"
  fuelmenu_sha: "78ffc73065a9674b707c081d128cb7eea611474f"
  shotgun_sha: "63645dea384a37dde5c01d4f8905566978e5d906"
  network-checker_sha: "a43cf96cd9532f10794dce736350bf5bed350e9d"
  fuel-upgrade_sha: "616a7490ec7199f69759e97e42f9b97dfc87e85b"
  fuelmain_sha: "d605bcbabf315382d56d0ce8143458be67c53434"