chore: remove feature flag owner

[nickoferrall]

With this PR, we can remove feature flag owners. I prefer creating a new mutation rather than updating applyFeatureFlag because I think it's better to have distinct names to make it clearer for the sales team.

To Test

Add a feature flag, apply a feature flag to a subject, e.g. an orgId, and the remove it like so:

mutation { 
  removeFeatureFlagOwner(flagName: "hasSingleColumnStandupsFlag", subjects: {
    orgIds: ["AQQ5zJw652"]
  }
  ) {
    __typename
    ... on RemoveFeatureFlagOwnerSuccess {
      organizations {
  name
        featureFlag(featureName: "hasSingleColumnStandupsFlag")
      }
    }
    ... on ErrorPayload {
      error {
        message
      }
    }  
  }
}

[Dschoordsch]

Did not test

[Dschoordsch]

+1 Might just be me, but I find this name confusing: removing the owner of the feature flag sounds backwards. If I take your candy, did I remove you as the owner from that candy?
I would just call it removeFeatureFlag.

[nickoferrall]

Haha yeah, but as there's featureFlag and featureFlagOwner, I'd prefer to explicitly say we're removing the owner. There's already a deleteFeatureFlag mutation, which could get confusing