## Description
- Updates `wsbuilder` to return a `BuildError` with
`http.StatusBadRequest` to signify a "validation error" on missing or
invalid parameters
- Adds a short-circuit in `prebuilds.StoreReconciler` to mark presets
for which creating a build returns a "validation error" as "validation
failed" and skip further attempts to reconcile.
- Adds a test to verify the above
- Introduces a new Prometheus metric
`coderd_prebuilt_workspaces_preset_validation_failed` to track the above
Closes: https://github.com/coder/coder/issues/21237
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Co-authored-by: Cian Johnston <cian@coder.com>
Susana Ferreira