I think it is fine. As long as you did not initiate the work and do the work, which it sounds like you didn't. Kids at 7 can't be expected to figure out material science, and you only helped by "bringing the fix", she did the final fix. And, as long as you did not get emotionally vested in the success/failure of the project (which again, sounds like you controlled). It is only a school project for a 7-yr old, afterall, and her learning from it is most important, not the final end-product.
One of my pet-peeves is school-projects where parents go WAY-overboard to help the child create "museum-perfect" displays...it becomes a project of who can outspend themselves at Michael's (a craft store), or some science store. I've seen Kindergarten projects submitted by kids (who can barely manage using a scissor and cut or draw stick figures) that are "museum-worthy" 3-D displays complete with fake pond-water to emulate a marsh, live gekkos, live insect eggs ready to hatch (store bought) etc. etc.
That's "hovering"!!
Luckily, we moved to a GT school program where teachers have the kids do most of the big projects and assignments at school, specifically to ensure student autonomy, creativity and independence.