Ignore token column in deploy_tokens table

What does this MR do and why?

This takes care of the first step of #199249 (closed) (following the migrations guide), by ignoring the token column in deploy_tokens model. Additionally, we update the authentication token field encrypted strategy to be required to ensure we are only looking up the encrypted field instead of looking up both columns moving forward.

MR acceptance checklist

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Related to #199249 (closed)