Improve VRAM compression format in Detect 3D editor message

[Calinou]

Previously, the format displayed was always S3TC/ETC/BPTC. It now matches what is defined in the project settings, the current platform and import defaults.

Preview

On desktop platforms by default:

res://example.jpg: Texture detected as used in 3D. Enabling mipmap generation and setting the texture compression mode to VRAM Compressed (S3TC).

On desktop platforms, with High Quality enabled in the import defaults:

res://example.jpg: Texture detected as used in 3D. Enabling mipmap generation and setting the texture compression mode to VRAM Compressed (BPTC).