gitlab-experiment is using an outdated schema

https://gitlab.com/gitlab-org/gitlab/-/blob/13b7598ac95fa214235a8c20339b8c59308693df/config/initializers/gitlab_experiment.rb#L70, and https://gitlab.com/gitlab-org/gitlab/-/blob/13b7598ac95fa214235a8c20339b8c59308693df/app/assets/javascripts/experimentation/constants.js#L1 are using an old version of the schema. The newer version (1-0-3) should be used, notably because of the additional possible length for the context key when using sha2.

Use https://gitlab.com/gitlab-org/iglu/-/blob/master/public/schemas/com.gitlab/gitlab_experiment/jsonschema/1-0-3

@jayswain, this may need to be communicated to the data team or the analytics teams? Maybe even product intelligence, as I'm not sure who managed the database tables in snowflake, but they may need to increase the column size for the keys from 32 to 64.