The answer to a question of style will always be, it depends. In the example given, I'd say that the minor action disrupts the dialog, but that's without knowing the context of this excerpt. And this is meant to be an example. There's no rule for how to place minor detail, but there are helpful ways to think about it.
Every reader imagines the story a little differently. How much detail to provide is a writer's choice. The choices made will, over time, make up their style.
Minor details are generally given to flesh out a world. The color of someone's eyes, the make of a car, the address of someone's apartment—these are all examples of details that are given to make a world seem more real. The person's face, the car, the apartment—these are details that will guide the reader's imagination towards the picture the author has in mind. Similarly, minor actions can give context to a character's larger actions, bringing a character's behavior closer to what a writer wants. If all goes well, this will result in well-drawn locations and characters.
You may say, this is all excellent, but how does it help?
When asking where to place a minor detail or action, you might do better than looking at any one example. Have a look at your own writing. In particular, try to find some favorite passages, ones you feel worked well. Bits of action and description that you're proud of.
Where did you put colorful details? Did you interrupt dialog? Did you find clever ways to work it in? Did you have expository sections? There are no correct choices, only the ones that work.
Try to find commonalities between these passages and use that as a guide, but don't be bound by anything. Know your strengths, but don't worry about taking risks.