fix: stop reading deployment environment responses

[alongubkin]

Summary

• derive the post-create environment variable count from the submitted request
• stop reading environment variables back from the deployment response
• preserve the existing human-readable success output

Validation

• rustfmt --edition 2021 --check crates/alien-cli/src/commands/deployments.rs
• cargo check -p alien-cli

[greptile-apps]

Greptile Summary

This PR stops relying on deployment responses to echo environment variables while preserving the human-readable success output.

• Captures the environment-variable count directly from the validated request collection.
• Prints that submitted count after successful deployment creation.
• Omits the environment-variable line when no variables were submitted.

Confidence Score: 5/5

The PR appears safe to merge.

The captured count exactly matches the validated environment-variable vector moved into the deployment request, and the change preserves the existing human output without depending on response-field availability.

Important Files Changed

Filename	Overview
crates/alien-cli/src/commands/deployments.rs	Counts the validated environment variables before moving them into the create request and uses that count in human-readable success output; no actionable defect was identified.

_{Reviews (1): Last reviewed commit: "fix: stop reading deployment environment..." | Re-trigger Greptile}