It should be okay as long as you don't double back on the first day and camp on the JMT somewhere.
I have a feeling that these kind of questions will come up more often with only the Happy Isles pass-through permit having a Donahue exit now.
In 2020 when I did the JMT from Happy Isles, I originally had a Glacier Point to Little Yosemite Valley permit with Donahue exit, but lucked out a few weeks before my JMT started and got a HI pass-through permit. I was planning on doing a HI to Nevada Falls day hike the day before to get that part of the JMT out of the way.
Although it's a bit further down the trail than the no camping zone (maybe an extra mile), there is a great area to camp with a great view of the area and Mt Starr King at 37.69329, -119.53328.
WanderingJim