The I2C Breakout shield offers 2 sets of STEMMA/QWIIC connectors and pin headers in 2 different 3v3 power rails.
The first has 3v3 power always on.
The second has user controlled 3V3 power that is off by default, so when you put your ESP32 into deep sleep, the 3V3 power for the I2C devices on that i2C bus get shut down automatically.