Move Landing page bundle configs to the default recipe config dir on 9.2.x

Problem/Motivation

On the 9.2.x branch, the default recipe grants Landing page content-type permissions before the node.type.landing_page bundle (in config/optional) is guaranteed to exist, so the grants are silently dropped ("Non-existent permission(s) assigned to roles"). Fixed the same way on 10.1.x, see #3535703.

Steps to reproduce

Proposed resolution

Port the 10.1.x fix: move the Landing page bundle configs from config/optional into recipes/default/config so the Recipe system imports them before applying grantPermissions.

Remaining tasks

• ✅ File an issue about this project
• ✅ Addition/Change/Update/Fix to this project
• ✅ Testing to ensure no regression
• ➖ Automated unit/functional testing coverage
• ➖ Developer Documentation support on feature change/addition
• ➖ User Guide Documentation support on feature change/addition
• ➖ UX/UI designer responsibilities
• ➖ Accessibility and Readability
• ✅ Reviewed by a human
• ✅ Code review by maintainers
• ✅ Full testing and approval
• ✅ Credit contributors
• ✅ Review with the product owner
• ✅ Update Release Notes
• ✅ Release varbase-9.2.0, varbase_landing-9.2.4

User interface changes

• N/A

API changes

• N/A

Data model changes

• N/A

Release notes snippet

• fix: #3608599 Move Landing page bundle configs to the default recipe config dir