Revert PSRAM usage as it lead to memory fragmentation.

See https://github.com/jomjol/AI-on-the-edge-device/issues/2200 for details

code/sdkconfig.defaults

@@ -100,8 +100,8 @@ CONFIG_SPIRAM_MALLOC_ALWAYSINTERNAL=16384
 CONFIG_SPIRAM_MALLOC_RESERVE_INTERNAL=40960
 CONFIG_SPIRAM_CACHE_WORKAROUND=y
 CONFIG_SPIRAM_IGNORE_NOTFOUND=y
-CONFIG_SPIRAM_TRY_ALLOCATE_WIFI_LWIP=y
-CONFIG_SPIRAM_ALLOW_BSS_SEG_EXTERNAL_MEMORY=y
+#CONFIG_SPIRAM_TRY_ALLOCATE_WIFI_LWIP=y => Leads to memory fragmentation, see https://github.com/jomjol/AI-on-the-edge-device/issues/2200
+#CONFIG_SPIRAM_ALLOW_BSS_SEG_EXTERNAL_MEMORY=y => Leads to memory fragmentation, see https://github.com/jomjol/AI-on-the-edge-device/issues/2200
 
 CONFIG_ESP_INT_WDT_TIMEOUT_MS=300
 
@@ -123,7 +123,7 @@ CONFIG_MQTT_TASK_CORE_SELECTION_ENABLED=y
 CONFIG_MQTT_USE_CORE_0=y
 CONFIG_MQTT_USE_CUSTOM_CONFIG=y
 #CONFIG_MQTT_OUTBOX_EXPIRED_TIMEOUT_MS=5000
-#CONFIG_MQTT_CUSTOM_OUTBOX=y # -> Use custom outbox in components/jomjol_mqtt/mqtt_outbox.h/cpp. If USE_PSRAM is enabled in there, it will save 10 kBytes of internal RAM.
+#CONFIG_MQTT_CUSTOM_OUTBOX=y # -> Use custom outbox in components/jomjol_mqtt/mqtt_outbox.h/cpp. If USE_PSRAM is enabled in there, it will save 10 kBytes of internal RAM. How ever it also leads to memory fragmentation, see https://github.com/jomjol/AI-on-the-edge-device/issues/2200
 
 CONFIG_FREERTOS_TASK_FUNCTION_WRAPPER=n