swapchain: add a case for minImageCount in capabilities

When creating a swapchain around a single-buffered SurfaceTexture, the
VkSurfaceCapabilitiesKHR structure obtained was giving a minImageCount
of 2 and a maxImageCount of 1, which should both be 1 in this case.

Test: create a swapchain around a single-buffered SurfaceTexture should
give back 1 as minImageCount from VkSurfaceCapabilitiesKHR
Bug: b/77825831

Change-Id: Ic42c29a93c6e9c818dbf735be5ce10b58cdb44d9