LED light bulb in series or parallel?
It's likely a combination of series and parallel, arranged for the target drive voltage and depending on both Vf and the number of LEDs in each string.

Parallel LEDs have issues with Vf matching and therefore, brightness. So series arrangement is preferred as it evens out brightness in the string, and can be controlled by a single PWM current-regulated source. The currents required are smaller, so wiring and traces are more compact.

And indeed, if one LED fails in a string, the whole string goes bad. To mitigate this the designers count on the fact that LEDs have a very long life (20-50k hours) compared to incandescent bulbs, so it's practical to wire them this way.