(1P) SPT: set template title using __experimentalOnReady property

[retrofox]

Once WordPress/gutenberg#17242 🚢 🤞, apply the needed changes in order to simplify the current implementation.

[github-actions]

This issue is stale because it has been 180 days with no activity. You can keep the issue open by adding a comment. If you do, please provide additional context and explain why you’d like it to remain open. You can also close the issue yourself — if you do, please add a brief explanation and apply one of relevant issue close labels.

[github-actions]

This issue is stale because 720 days have passed with no activity. A member of @kitkat-team will review and if required close this issue within 7 days. If you disagree and would like this issue to remain open, please provide additional context, updated reproduction steps and/or screenshots.