Fix sense of device set membership checks

The flasher Bash script uses a neat `"${FILENAME##*"$variant"*}"` Bash trick to replace any string in `FILENAME` containing the string in `variant` with an empty string. It puts this in loops over arrays to check if `FILENAME` contains any `variant` in the list.

But the test needs to be `-z` (i.e. match the empty string, which we get if we found `variant`) if we want to operate on filenames that have any items from the list. With `-n` we pass the condition if we *don't* find the variant, and then operate on filenames that *don't* have *every* variant from the list.

bin/device-install.sh

@@ -138,7 +138,7 @@ if [ -f "${FILENAME}" ] && [ -n "${FILENAME##*"update"*}" ]; then
 
 	# littlefs* offset for BigDB 8mb and OTA OFFSET.
 	for variant in "${BIGDB_8MB[@]}"; do
-		if [ -n "${FILENAME##*"$variant"*}" ]; then
+		if [ -z "${FILENAME##*"$variant"*}" ]; then
 			OFFSET=0x670000
 			OTA_OFFSET=0x340000
 		fi
@@ -146,7 +146,7 @@ if [ -f "${FILENAME}" ] && [ -n "${FILENAME##*"update"*}" ]; then
 
 	# littlefs* offset for BigDB 16mb and OTA OFFSET.
 	for variant in "${BIGDB_16MB[@]}"; do
-		if [ -n "${FILENAME##*"$variant"*}" ]; then
+		if [ -z "${FILENAME##*"$variant"*}" ]; then
 			OFFSET=0xc90000
 			OTA_OFFSET=0x650000
 		fi
@@ -155,7 +155,7 @@ if [ -f "${FILENAME}" ] && [ -n "${FILENAME##*"update"*}" ]; then
 	# Account for S3 board's different OTA partition
 	# FIXME: Use PlatformIO info to determine MCU type, this is unmaintainable
 	for variant in "${S3_VARIANTS[@]}"; do
-		if [ -n "${FILENAME##*"$variant"*}" ]; then
+		if [ -z "${FILENAME##*"$variant"*}" ]; then
 			MCU="esp32s3"
 		fi
 	done