[Feat] (MG_Backend, MG_Util): give a cube map array real storage on DirectGLES

TextureCubeMapArray was missing from every storage and upload switch in the
DirectGLES texture sync, so a cube map array reached the driver with no storage
at all - and from the glFramebufferTextureLayer branch, so attaching one of its
layers fell through to glFramebufferTexture2D and raised INVALID_ENUM. Every
GL_TEXTURE_CUBE_MAP_ARRAY colour check in
direct_state_access.framebuffers_texture_layer_attachment read nothing.

ES 3.2 has GL_TEXTURE_CUBE_MAP_ARRAY natively and it stores exactly like a 2D
array whose depth is six times the cube count, so each switch gains the case
beside Texture2DArray and nothing else changes. 1D arrays join the layer branch
for the same reason - their backend image is a 2D array.

Per the POST rule the new GLES dependency gets a capability
(SupportsTextureCubeMapArray, ES 3.2 core or EXT/OES_texture_cube_map_array) and
a DriverPost row saying what a user loses without it.

Takes framebuffers_texture_layer_attachment from failing to passing on Espryt. It
still fails on DirectVulkan, which declines a layered attachment outright.

MobileGL/MG_Util/BackendLoaders/OpenGL/Loader.cpp

@@ -837,6 +837,10 @@ namespace MobileGL::MG_Util::BackendLoader {
                     std::strcmp(extension, "GL_OES_texture_border_clamp") == 0) {
                     caps.SupportsTextureBorderClamp = true;
                 }
+                if (std::strcmp(extension, "GL_EXT_texture_cube_map_array") == 0 ||
+                    std::strcmp(extension, "GL_OES_texture_cube_map_array") == 0) {
+                    caps.SupportsTextureCubeMapArray = true;
+                }
                 if (std::strcmp(extension, "GL_EXT_base_instance") == 0) {
                     caps.SupportsBaseInstance = true;
                 }
@@ -1021,6 +1025,7 @@ namespace MobileGL::MG_Util::BackendLoader {
         // Core from ES 3.2 on, whatever the extension string says.
         if (caps.GLESVersion.Major > 3 || (caps.GLESVersion.Major == 3 && caps.GLESVersion.Minor >= 2)) {
             caps.SupportsTextureBorderClamp = true;
+            caps.SupportsTextureCubeMapArray = true;
         }
         if (caps.SupportsTextureFilterAnisotropy) {
             GLfloat maxTextureMaxAnisotropy = 1.0f;

MobileGL/MG_Util/BackendLoaders/OpenGL/Loader.h

@@ -1045,6 +1045,8 @@ namespace MobileGL {
             // EXT/OES_texture_border_clamp before that. Without it every border-colour parameter
             // raises INVALID_ENUM on the driver, so the syncs have to be gated on it.
             Bool SupportsTextureBorderClamp = false;
+            // GL_TEXTURE_CUBE_MAP_ARRAY: ES 3.2 core, or EXT/OES_texture_cube_map_array before it.
+            Bool SupportsTextureCubeMapArray = false;
             // GL_MAX_TEXTURE_MAX_ANISOTROPY_EXT of the host driver; only queried when the
             // extension above is present, and left at 1.0 (no anisotropy) otherwise.
             Float MaxTextureMaxAnisotropy = 1.0f;