samples: esp32: do not search for all regions

Current SPIRAM sample code tries to search for any available
heap, causing this test to fail. Make sure the sample code
only malloc data from external ram.

Fixes #65997

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

Author: sylvioalves

samples/boards/esp32/spiram_test/boards/esp32_devkitc_wroom.conf

@@ -1,3 +1,4 @@
 CONFIG_ESP_SPIRAM=y
 CONFIG_ESP_HEAP_MIN_EXTRAM_THRESHOLD=2048
 CONFIG_HEAP_MEM_POOL_SIZE=98304
+CONFIG_ESP_HEAP_SEARCH_ALL_REGIONS=n