dont glue a camera to it. a phototransistor or BH1750 next to the led into an esphome binary_sensor / adc is enough.
if the led blinks on alarm, use delayed_off so one blink becomes a stuck ON. if it just changes color, two ldrs with tape over each color works, ugly but it works.
better long term is a first alert z-wave / nest protect you can actually talk to. optical kludge will false on sunlight and nightlights.