Providers Lock Platform Separate Value

Fixed space-delimited flag values in providers lock

The space-delimited form, providers lock -platform linux_amd64, now reaches OpenTofu and Terraform intact. Previously it was the attached form, -platform=linux_amd64, that worked: given the value as a separate argument, Terragrunt moved it to the end of the command, where it was read as a provider address and the run failed with Invalid provider type "linux_amd64".

-fs-mirror and -net-mirror were moved the same way, and now keep their values too.

With --provider-cache enabled, platforms are also split correctly across the per-platform providers lock runs used to warm the cache.