You just bend it out of the way......
I'm in the middle of this same install myself.
If you bend the dipstick tube to the rear to get into the indentation in the block, it puts the tube on the RHS of the plug. In this position, it looks like the plug will be difficult to get out and the tube bracket to the head will need to be extended with a bracket to reach the original mounting position on the head.
JBA wasn't much help yesterday on the phone. Seems they don't want to confess they wrapped the header too tight to the block even though they had room to move it out to clear the tube.
Have you installed the JBA's on a V6 where you found the sweet spot to place the tube?