[data/preprocessors] feat: allow encoders to be used in append mode

[martinbomio]

Why are these changes needed?

This is part of #48133. Continuing the approach taken in #49426, make all the encoders work in append mode

Related issue number

#49426

Checks

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• I've included any doc changes needed for https://docs.ray.io/en/master/.
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    method in Tune, I've added it in doc/source/tune/api/ under the
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• Testing Strategy
  • Unit tests
  • Release tests
  • This PR is not tested :(

[martinbomio]

cc @richardliaw