FAQ / BLHeli 32.9 safety warning

# FAQ / BLHeli 32.9 full-throttle safety warning - 32.9 along with Betflight 4.4.0, 4.4.1, 4.5 pre-RC1 had a serious safety issue that could cause ESC to go full-throttle. - For 32.9, recommend disable DSHOT-BEACON for added safety. - However, If you are stuck on 32.9, be hyper cautious when plugging in - Use Betaflight released 4.4.2+ or 4.5.x+ where `DShot motor 0` packets are sent for safety purposes. (where "+" means "and later") - https://github.com/betaflight/betaflight/pull/12544 - https://github.com/betaflight/betaflight/pull/12560 #### Potentially related, unclear: - https://github.com/betaflight/betaflight/pull/12709