Nullify user roles with software developer value
What does this MR do?
On October 20th code was deployed (!16583 (merged)) to GitLab.com which caused profile save actions from any user to update the role attribute to a value of 0 (software developer). From October 21st, 16:47 CEST until October 23rd, 19:11 CEST, the new signup flow experiment was run, which forced 10% of users created in that timeframe to pick a role. October 24th (merged October 28th, not yet deployed: !19085 (merged)) a fix was created for the unintentional saving of the role.
Solution: after the fix is deployed (check with /chatops run auto_deploy status aac40d26), we should nullify all roles with a value of 0. Other values are intentional and should be kept. Unfortunately, we must also nullify roles with a value of software developer for users created within the timeframe the experiment was run, because, based on the database, we cannot distinguish between users that participated in the experiment and users in the control group.