Restore GLES support for BGR/ARGB/BGRA/ABGR texture formats via swizzle

[Copilot]

ANGLE GLES no longer exposed several common jME image formats that remain supported on the desktop GL path: BGR8, ARGB8, BGRA8, and ABGR8, including sRGB variants. This change restores those formats on GLES by mapping them to GLES-supported upload formats and applying texture swizzles to preserve channel order.

• GLES format mappings

  • Add GLES 3 mappings for BGR8, ARGB8, BGRA8, and ABGR8
  • Add matching sRGB mappings for the same formats
  • Use swizzled RGB8 / RGBA8 and SRGB8 / SRGB8_ALPHA8 internal formats instead of desktop-only byte-order upload formats

• Texture swizzle handling

  • Extend TextureUtil swizzle setup to cover the restored byte-order formats
  • Preserve expected channel semantics after upload on GLES without changing the desktop GL path

• Focused coverage

  • Update GLImageFormatsTest to assert that GLES 3 now exposes these formats through swizzled mappings in both linear and sRGB paths

// GLES 3 now exposes byte-order formats through swizzled RGB/RGBA uploads.
formatSwiz(formatToGL, Format.BGR8,  GL2.GL_RGB8,    GL.GL_RGB,  GL.GL_UNSIGNED_BYTE, true, false, true);
formatSwiz(formatToGL, Format.ARGB8, GLExt.GL_RGBA8, GL.GL_RGBA, GL.GL_UNSIGNED_BYTE, true, false, true);

formatSrgbSwiz(formatToGL, Format.BGR8,  GLExt.GL_SRGB8_EXT,        GL.GL_RGB,  GL.GL_UNSIGNED_BYTE, false, false, true);
formatSrgbSwiz(formatToGL, Format.ARGB8, GLExt.GL_SRGB8_ALPHA8_EXT, GL.GL_RGBA, GL.GL_UNSIGNED_BYTE, true,  false, true);