support default grok in generate object for twitter plugin

[agentdeveloper]

Is your feature request related to a problem? Please describe.

the default grok model should be supported for trimTokens in the generate Object in core currently type TiktokenModel and type TiktokenEncoding aren't supporting the default "grok-2-1212". right now it seems to be missing inside the core package

Describe the solution you'd like

I'd like to be able to use the twitter plugin without commenting out the token trimming.

Describe alternatives you've considered

just commenting out token trimming seemed to have allowed it to work.

Additional context

This is on the current release, not sure

[github-actions]

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