cogl/driver/gles: Handle reading RGBA1010102 too

This means can read without loosing precision, compared to if we read a
texture as rgb8.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/2461>

cogl/cogl/driver/gl/gles/cogl-driver-gles.c

@@ -280,6 +280,13 @@ _cogl_driver_read_pixels_format_supported (CoglContext *context,
   if (glformat == GL_RGBA && gltype == GL_UNSIGNED_BYTE)
     return TRUE;
 
+  if (glintformat == GL_RGB10_A2_EXT &&
+      glformat == GL_RGBA &&
+      gltype == GL_UNSIGNED_INT_2_10_10_10_REV_EXT &&
+      _cogl_has_private_feature (context,
+                                 COGL_PRIVATE_FEATURE_TEXTURE_FORMAT_RGBA1010102))
+    return TRUE;
+
   return FALSE;
 }