test: fix compute planner fixtures for persistent storage encryption key

[alongubkin]

ALIEN-1477. alien-core tests don't compile on main (d07764433): #1000 added compute planner tests that build PersistentStorage without the encryption_key field #1005 added. The two PRs merged one after the other, so each passed CI alone. cargo test -p alien-core fails with E0063 at compute_planner.rs 1312, 1462 and 1518. Main's Tests workflow is skipped on push, so it only shows on PRs whose test selection includes alien-core.

This sets encryption_key: None in the three fixtures. Test-only, no behavior change.

Checked in a Linux sandbox on main (via #1012, which merges main) + this commit: cargo check --workspace --all-targets is clean, cargo nextest run -p alien-core 660/660 pass.

🤖 Generated with Claude Code

[alongubkin]

@greptileai review

[greptile-apps]

Confidence Score: 5/5

[Low impact] This PR appears safe to merge; it supplies a missing field in three test fixtures.

Summary

Adds encryption_key: None to three PersistentStorage fixtures in compute_planner.rs.

• Compute planner fixtures now include the optional encryption key field.

_{Reviews (1) · Last reviewed commit: "test: set encryption_key in the compute ..." · Reviewed by Greptile}