Remove the bulb and then turn the the light "ON" at the switch. Does it still trip the GFCI? If so you need a new light. If not, get any incandescent light, put it into the fixture, and see if it will light. If it will without tripping the GFCI the fixture is probably OK.
You had given me good advice here, but I skipped a step. I had removed the bad bulb, changed the seal, and replaced with an incandescent and it worked for 1 week but some tripping issue on my GFCI.
I ordered a replacement bulb in case it was faulty, but I’ll go back to the step where you said to test without a bulb plugged in, but I’m assuming it will work if it changing the bulb worked for 1 week.
I’ll check the fixture for any water penetration, but I didn’t see any way I had previously taken it out.