Adds support for updating Schema state fields.

[acrites]

On the Dataflow runner we already populate the encoding positions fields of the schema proto whenever the pipeline is updated with changes to the schema. This correctly updates any schemas used as inputs/outputs to DoFn's. For the portable runner, we don't update the schemas used by persistent state fields however. These just use whatever schema is compiled in.

So this PR factors out the code from the Dataflow runner that updates these schemas and reuses this code in the Java SDK.

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[github-actions[bot]]

Checks are failing. Will not request review until checks are succeeding. If you'd like to override that behavior, comment assign set of reviewers

[scwhittle]

retriggering tests

[acrites]

assign set of reviewers

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R: @kennknowles for label java.

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[github-actions[bot]]

Reminder, please take a look at this pr: @kennknowles

[kennknowles]

R: @ahmedabu98

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[ahmedabu98]

Failing tests are not related