It's not enough that "light" exists in general, somewhere else, and we have no Sun! Plants can't live with that.
I am surprised you guys want to deviate from the science of Genesis where the writer made sure he took down notes while God spoke and it was like he heard that the water was divided by the sky, and then gathered into one place and that allowed the land to emerge, and then the plants were created and brought in from somewhere else (reflecting on the second creation story in Genesis).
Sticking with Genesis, the plants are here BEFORE the Sun.
But not before light, which we don't know how much there was at that point so it's not possible to say that there wasn't enough for plants to survive.