Block all tasks (not interrupts) during flash erase

Otherwise we risk running code from flash while an erase is in
progress, crashing and corrupting the file system.

Related to #3744

Author: tannewt

ports/esp32s2/esp-idf-config/sdkconfig.defaults

@@ -717,10 +717,8 @@ CONFIG_SPI_FLASH_DANGEROUS_WRITE_ABORTS=y
 # CONFIG_SPI_FLASH_DANGEROUS_WRITE_ALLOWED is not set
 # CONFIG_SPI_FLASH_USE_LEGACY_IMPL is not set
 # CONFIG_SPI_FLASH_BYPASS_BLOCK_ERASE is not set
-CONFIG_SPI_FLASH_YIELD_DURING_ERASE=y
-CONFIG_SPI_FLASH_ERASE_YIELD_DURATION_MS=20
-CONFIG_SPI_FLASH_ERASE_YIELD_TICKS=1
-CONFIG_SPI_FLASH_WRITE_CHUNK_SIZE=8192
+# CONFIG_SPI_FLASH_YIELD_DURING_ERASE is not set
+CONFIG_SPI_FLASH_WRITE_CHUNK_SIZE=4096
 # CONFIG_SPI_FLASH_SIZE_OVERRIDE is not set
 
 #