samples: add nrf54l15dk support

[ktaborowski]

KRKNWK-19447

CI parameters

Github_actions:
  #(branch, hash, pull/XXX/head)
  NRF_revision: main

  # Do not change after creating PR
  Create_NRF_PR: false
Jenkins:
  test-sdk-sidewalk: nrf54l15dk_nrf54l15_cpuapp

Description

JIRA ticket:

Self review

• There is no commented code.
• There are no TODO/FIXME comments without associated issue ticket.
• Commits are properly organized.
• Change has been tested.
• Tests were updated (if applicable).

[github-actions]

Sample		diff	used	total
nrf54l15pdk/nrf54l15/cpuapp:sample.sidewalk.dut	RAM	-139.14 KB	0 B	0 B
	ROM	-495.97 KB	0 B	0 B
nrf54l15pdk/nrf54l15/cpuapp:sample.sidewalk.dut.no_secure	RAM	-139.12 KB	0 B	0 B
	ROM	-485.11 KB	0 B	0 B
nrf54l15pdk/nrf54l15/cpuapp:sample.sidewalk.hello	RAM	-116.61 KB	0 B	0 B
	ROM	-441.76 KB	0 B	0 B
nrf54l15pdk/nrf54l15/cpuapp:sample.sidewalk.hello.ble_only	RAM	-89.9 KB	0 B	0 B
	ROM	-346.07 KB	0 B	0 B
nrf54l15pdk/nrf54l15/cpuapp:sample.sidewalk.hello.ble_only.release	RAM	-85.12 KB	0 B	0 B
	ROM	-278.34 KB	0 B	0 B
nrf54l15pdk/nrf54l15/cpuapp:sample.sidewalk.hello.release	RAM	-100.51 KB	0 B	0 B
	ROM	-354.6 KB	0 B	0 B
nrf52840dk/nrf52840:sample.sidewalk.demo	RAM	16 B	118.53 KB	0 B
	ROM	104 B	432.14 KB	0 B
nrf52840dk/nrf52840:sample.sidewalk.demo.ble_only	RAM	16 B	103.2 KB	0 B
	ROM	104 B	354.65 KB	0 B
nrf52840dk/nrf52840:sample.sidewalk.dut	RAM	16 B	142.11 KB	0 B
	ROM	104 B	496.42 KB	0 B
nrf52840dk/nrf52840:sample.sidewalk.dut.no_secure	RAM	16 B	142.09 KB	0 B
	ROM	104 B	487.9 KB	0 B
nrf52840dk/nrf52840:sample.sidewalk.hello	RAM	16 B	119.7 KB	0 B
	ROM	104 B	446.82 KB	0 B
nrf52840dk/nrf52840:sample.sidewalk.hello.ble_only	RAM	16 B	93.02 KB	0 B
	ROM	104 B	352.91 KB	0 B
nrf52840dk/nrf52840:sample.sidewalk.hello.ble_only.release	RAM	16 B	88.2 KB	0 B
	ROM	104 B	289.61 KB	0 B
nrf52840dk/nrf52840:sample.sidewalk.hello.release	RAM	16 B	103.55 KB	0 B
	ROM	104 B	364.41 KB	0 B
nrf54l15pdk/nrf54l15/cpuapp:sample.sidewalk.demo	RAM	-115.23 KB	0 B	0 B
	ROM	-427.1 KB	0 B	0 B
nrf54l15pdk/nrf54l15/cpuapp:sample.sidewalk.demo.ble_only	RAM	-99.86 KB	0 B	0 B
	ROM	-347.84 KB	0 B	0 B
nrf54l15dk/nrf54l15/cpuapp:sample.sidewalk.dut	RAM	139.21 KB	139.21 KB	0 B
	ROM	498.04 KB	498.04 KB	0 B
nrf54l15dk/nrf54l15/cpuapp:sample.sidewalk.dut.no_secure	RAM	139.19 KB	139.19 KB	0 B
	ROM	487.18 KB	487.18 KB	0 B
nrf54l15dk/nrf54l15/cpuapp:sample.sidewalk.hello	RAM	116.68 KB	116.68 KB	0 B
	ROM	443.78 KB	443.78 KB	0 B
nrf54l15dk/nrf54l15/cpuapp:sample.sidewalk.hello.ble_only	RAM	90.31 KB	90.31 KB	0 B
	ROM	354.59 KB	354.59 KB	0 B
nrf54l15dk/nrf54l15/cpuapp:sample.sidewalk.hello.ble_only.release	RAM	85.53 KB	85.53 KB	0 B
	ROM	284.59 KB	284.59 KB	0 B
nrf54l15dk/nrf54l15/cpuapp:sample.sidewalk.hello.release	RAM	100.58 KB	100.58 KB	0 B
	ROM	356.28 KB	356.28 KB	0 B
nrf54l15dk/nrf54l15/cpuapp:sample.sidewalk.demo	RAM	115.3 KB	115.3 KB	0 B
	ROM	429.13 KB	429.13 KB	0 B
nrf54l15dk/nrf54l15/cpuapp:sample.sidewalk.demo.ble_only	RAM	100.26 KB	100.26 KB	0 B
	ROM	356.36 KB	356.36 KB	0 B