boards: heltec: fix kconfig cpu entry name

Minimum heap pool should be always set for the board
in order to enable internal drivers/subsystems to work.

It is currently not defined for APPCPU due to typo in
board's Kconfig, possibly causing build failures.

Fixes #81218

Signed-off-by: Sylvio Alves <[email protected]>

Author: sylvioalves

boards/heltec/heltec_wireless_stick_lite_v3/Kconfig

@@ -4,4 +4,4 @@
 config HEAP_MEM_POOL_ADD_SIZE_BOARD
 	int
 	default 4096 if BOARD_HELTEC_WIRELESS_STICK_LITE_V3_ESP32S3_PROCPU
-	default 256 if BOARD_HELTEC_WIRELESS_STICK_LITE_V3_ESP32S3_PROCPU
+	default 256 if BOARD_HELTEC_WIRELESS_STICK_LITE_V3_ESP32S3_APPCPU