Added a 4MiB flash partitioning variant for ESP32S3: adds support for 4MiB discrete flash boards or ESP32-S3FH4R2 with embedded 4MiB flash based ones. Tested on the waveshare ESP32-S3 Mini w/ESP32-S3FH4R2. Signed-off-by: Stanislav Ponomarev <me@stasponomarev.com>