renderer/OpenGL: revert change to compressed texture format

This was applied to the wrong thing by accident, making the custom
shader ping-pong textures compressed, which breaks custom shaders
because compressed texture formats are not color renderable.

Additionally, I've not switched the compressed format to the correct
texture options, because I tried that and it turns out that the default
compression applied by drivers can't be trusted to be good quality and
generally speaking looks terrible. In the future we can explore doing
the compression ourselves CPU-side with something like b7enc_rdo.

src/renderer/OpenGL.zig

@@ -395,7 +395,7 @@ pub inline fn textureOptions(self: OpenGL) Texture.Options {
     _ = self;
     return .{
         .format = .rgba,
-        .internal_format = .srgba_compressed,
+        .internal_format = .srgba,
         .target = .@"2D",
     };
 }