Post Topic should return error when non-existing blobHandle is passed

[Vadim-Bulavin]

1. Post topic

curl -X POST --header 'Content-Type: application/json' --header 'Accept: application/json' --header 'Authorization: SocialPlus TK=eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJhdWQiOiIzcjNGcnhjNVJLdFxuRmFjZWJvb2tcbjEzNDQ4MDkzMDg5NjA4ODAiLCJpc3MiOiIzdm4tNUJOZUFnV1xuZWMxNjY1YTQtOTIwZC00NDQ5LWI4YTAtNDllZDM3NGQ0MjkwIiwiZXhwIjoxNTI1Njg2ODM2fQ.6XE1Xh5Rslung-x2R1DRWlbd1Fr1cXJumIaCi2rGNSA' -d '{
  "title": "1",
  "text": "1",
  "blobType": "Image",
  "blobHandle": "EzAzCJ7gRQchpdh4mSjUqbx7"
}' 'https://ppe.embeddedsocial.microsoft.com/v0.7/topics'

Expected: receive error response, topic is not created.
Actual: topic is created, response code 201 is received with body:

{
  "topicHandle": "3qj2I_NwtrJ"
}