Check (and fix) Validators DApp according to upcoming changes in MetaMask

[varasev]

MetaMask will have some breaking changes soon: https://medium.com/metamask/breaking-changes-to-the-metamask-inpage-provider-b4dde069dd0a

Please check Validators DApp and fix it if needed.

[varasev]

MetaMask postponed the changes: https://medium.com/metamask/metamask-permissions-system-delay-retrospective-9c49d01039d6