scripts: memory-threshold: find_my: locator_tag: Add nRF54LM20 DK

Added nrf54lm20dk/nrf54lm20a/cpuapp board target to the Find My
Locator Tag sample targets in the memory threshold configuration.

Jira: NCSDK-34285

Signed-off-by: Mateusz Kapala <mateusz.kapala@nordicsemi.no>

Author: mkapala-nordic

scripts/memory-threshold-list.yaml

@@ -44,6 +44,7 @@
     - nrf5340dk/nrf5340/cpuapp/ns
     - nrf54l15dk/nrf54l10/cpuapp
     - nrf54l15dk/nrf54l15/cpuapp
+    - nrf54lm20dk/nrf54lm20a/cpuapp
     - nrf54h20dk/nrf54h20/cpuapp
   rom_increase: 1024
   ram_increase: 1024