Fix layer settings for shader_debugPrintf and reenable iOS Simulator execution

[SRSaunders]

Description

This PR contains the following:

1. Fixes a layer settings regression in the shader_debugPrintf sample for Release builds - all platforms.
2. Addresses a layer settings holdover problem in the Vulkan Samples framework when running in batch mode - all platforms.
3. Corrects a reversed DebugUtils and DebugReport callback setup in get_instance_create_info_extensions() - all platforms.
4. Re-enables samples to run on the iOS Simulator target by fixing a regression in the framework that incorrectly made VK_KHR_portability_enumeration mandatory - should be optional.
5. Completes the new layer settings framework transition work to allow layout_transitions, pipeline_barriers, and subpasses to compile and run for the iOS Simulator target.

Fixes #1496 and #1497.

Tested with Vulkan SDK 1.4.341 on: a) Windows 11, b) macOS Sequoia 15.7.4 (MoltenVK and KosmicKrisp), and c) iOS 26.2 on iOS Simulator.

General Checklist:

Please ensure the following points are checked:

• My code follows the coding style
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• My changes do not add any new validation layer errors or warnings
• I have used existing framework/helper functions where possible
• My changes do not add any regressions
• I have tested every sample to ensure everything runs correctly
• This PR describes the scope and expected impact of the changes I am making

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• I did a full batch run using the batch command line argument to make sure all samples still work properly

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[asuessenbach]

Great catches!

Thanks a lot for the corrections.