Add is_default key to cover photo
for a new opportunity, a new key is added is_default indicating a cover photo is default or not.
example response:
example response:
"cover_photo": {
"url": "https://s3.eu-west-1.amazonaws.com/gis-development/6s0cxvfp0pbcj9sd2odj13cxznok",
"filename": "default-cover-photo.jpg",
"is_default": true
}