refactored correct processing of validation errors for all workflows

[zippy]

PR summary

Fixes a bug where timeouts when fetching entry to validate were considered a validation fail rather than simply being retried.

testing/benchmarking notes

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followups

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changelog

• if this is a code change that effects some consumer (e.g. zome developers) of holochain core, then it has been added to our between-release changelog with the format

- summary of change [PR#1234](https://github.com/holochain/holochain-rust/pull/1234)

documentation

• this code has been documented according to our docs checklist