There are a number of ways to go about answering this sort of question, below are detailed the methods I usually use:
Specific Over General:
The two passages in question are (a):
"Anything the target is wearing or carrying is invisible as long as it is on the target’s person."
-- Invisibility Spell Description
"Until the spell ends, the object sheds bright light in a 20-foot radius and dim light for an additional 20 feet. The light can be colored as you like. Completely covering the object with something opaque blocks the light."
-- Light Spell Description
There are multiple ways of dealing with this, but the most basic would include:
The most recent effect takes effect. In this interpretation, the more specific one is the one that took effect last, so in your example, the light would vanish. This ruling maintains that the light an object creates is an aspect of the visual properties of an object, and thus invisibility should make them imperceivable.
Spells only do what they literally say. This ruling would say that the invisibility spell only makes objects and creatures invisible: nothing more, nothing less. By this interpretation, it is reasonable to argue that the light would linger even if its source was invisible. The light spell says nothing about you needing to see the object for its light to be visible, and this interpretation accounts for the fact that even if the object itself were around a corner or otherwise obscured you should still be able to see the light that it emits.
Only the creature holding the amulet can see the light. This perspective would be based on how magic might work in your world, where the invisible creature is shunted into some border ethereal realm. There is essentially no RAW or RAI support for this approach but it is a possible ruling I thought worth mentioning and could be used in certain campaigns where spell effects are a little less tied down by what the rules say is possible.
Think about it from the other side. What if your opponent is invisible, should your wizard be able to use a cantrip to completely negate that element of an encounter? Even with a saving throw that is still pretty powerful for a cantrip with no concentration requirement (compare to spells like faerie fire and see invisibility). Personally, if I cast greater invisibility, I don't want it to be negated by a cantrip.
Another possible situation that would derive from the same logic is what if you cast minor illusion over a light source? would the light remain visible even if its source is obscured?
What if the light is created by a magic item such as a Sunblade? Would invisibility negate the sunlight effect so useful against vampires (what if Strahd used greater invisibility as an offensive weapon on the creature wielding the Sunblade) or would the sunlight effects remain but the light no longer be shed?
Overall, you will need to make the choice for your own table. Personally, I would rule that the light would remain but the source would be invisible. This would allow the creature to maintain its invisibility but would allow an intelligent foe to know the creature's general location at any given time.