Drop samplerAnisotropy as a required GPU feature

Sampler anisotropy was made a required feature in an earlier commit due to its widespread availability but this was determined to be incorrect as certain Mali GPUs that can otherwise run 2D games in Skyline do not have this feature, while they are still not officially supported as this was the only roadblock to support them, it has now been made an optional feature.

app/src/main/cpp/skyline/gpu/trait_manager.h

@@ -16,6 +16,7 @@ namespace skyline::gpu {
         bool supportsSamplerMirrorClampToEdge{}; //!< If the device supports a mirrored clamp to edge as a sampler address mode (with VK_KHR_sampler_mirror_clamp_to_edge)
         bool supportsSamplerReductionMode{}; //!< If the device supports explicitly specifying a reduction mode for sampling (with VK_EXT_sampler_filter_minmax)
         bool supportsCustomBorderColor{}; //!< If the device supports a custom border color without format (VK_EXT_custom_border_color)
+        bool supportsAnisotropicFiltering{}; //!< If the device supports anisotropic filtering for sampling
         bool supportsLastProvokingVertex{}; //!< If the device supports setting the last vertex as the provoking vertex (with VK_EXT_provoking_vertex)
         bool supportsLogicOp{}; //!< If the device supports framebuffer logical operations during blending
         bool supportsVertexAttributeDivisor{}; //!< If the device supports a divisor for instance-rate vertex attributes (with VK_EXT_vertex_attribute_divisor)