Creating space with existing name

[KarimChabrak]

When user try to create a space with a name of an existing space he get a clear message asking to change the name.

But when creating a campaign with a title corresponding to an existing space name, they get an error message which is not clear for user. I propose to show a user friendly message that asks user to change "space name".

Issue when creating a campaign

Error message
{
"url": "/space/beyond-borders/xcoin/funding/new?challengeId=54",
"status": 400,
"response": {
"error": true,
"message": ""
},
"textStatus": "error",
"xhr": {
"readyState": 4,
"responseText": "{"error":true,"message":""}",
"responseJSON": {
"error": true,
"message": ""
},
"status": 400,
"statusText": "Bad Request"
},
"dataType": "json",
"error": true,
"message": "",
"errorThrown": "Bad Request",
"validationError": true
}