update top_project_contributions to project_contributions params for queries

[yuenmichelle1]

Updating responses for /classifications/users/:id?project_contributions=true for design:
https://www.figma.com/file/qbqbmR3t5XV6eKcpuRj7mG/Group-Stats?type=design&node-id=0-1&mode=design

Changes

• Instead of /classifications/users/:id?top_project_contributions=N , we now have a Boolean project_contributions that dictates whether or not the response will show ALL the user's project_contributions as an array of {project_id: __, count: ___}s (As opposed to having an Integer N top_project_contributions param.
• Response will no longer have the attribute unique_project_contributions with value of the unique project contributions count. (If one wants that count, they can check the length of the array of response['project_contributions']
• The plan is also to do this with user_groups. I.e. /classifications/user_groups/:id?project_contributions=true