Backends: Vulkan: added ImGui_ImplVulkan_CreateMainPipeline(). (#8110, #8111, #8053)

- Added ImGui_ImplVulkan_CreateMainPipeline(...) to explicitly re-create the main window pipeline (when some of its properties are changed).
- Does not implicitly use ImGui_ImplVulkan_InitInfo::PipelineRenderingCreateInfo, but a function parameter.
- The main window pipeline is created only if possible during ImGui_ImplVulkan_Init(...) (if a render pass or rendering info are given), else it should be created with ImGui_ImplVulkan_ReCreateMainPipeline(...)
- ImGui_ImplVulkan_CreatePipeline now takes a struct rather than (too) many parameters (and returns the created pipeline).
2 files changed