PSS: Allow pluggable state store configuration to be read from a plan file

[SarahFrench]

This PR is stacked on https://github.com/hashicorp/terraform/pull/37956

Whereas that PR allowed a plan operation to produce a plan file that described a state store, this PR enables apply operations that use a plan file to configure a state store using the data stored in the plan.

This new feature is tested by integration tests and an E2E test that shows the full init-plan-apply workflow when a pluggable state store is in use.

Target Release

1.15.x

Rollback Plan

• [x] If a change needs to be reverted, we will roll out an update to the code within 7 days.

Changes to Security Controls

Are there any changes to security controls (access controls, encryption, logging) in this pull request? If so, explain.

CHANGELOG entry

• [ ] This change is user-facing and I added a changelog entry.
• [x] This change is not user-facing.