manifest: update zephyr - allow sysbuild for nrf54

[nordic-piks]

Allow testing for PPR and FLPR core at nrf54

[NordicBuilder]

The following west manifest projects have been modified in this Pull Request:

Name	Old Revision	New Revision	Diff
zephyr	nrfconnect/sdk-zephyr@18285a0	nrfconnect/sdk-zephyr#1728	nrfconnect/sdk-zephyr#1728/files

Note: This message is automatically posted and updated by the Manifest GitHub Action.

[NordicBuilder]

Test specification

CI/Jenkins/NRF

• Integration Platforms

CI/Jenkins/integration

Test Module	File based changes	Manually selected	West overwrite
desktop52_verification	X
test-fw-nrfconnect-chip	X
test-fw-nrfconnect-fem	X
test-fw-nrfconnect-nfc	X
test-fw-nrfconnect-nrf-iot_cloud	X
test-fw-nrfconnect-nrf-iot_mosh	X
test-fw-nrfconnect-nrf-iot_positioning	X
test-fw-nrfconnect-nrf-iot_samples	X
test-fw-nrfconnect-nrf-iot_thingy91	X
test-fw-nrfconnect-nrf-iot_zephyr_lwm2m	X
test-fw-nrfconnect-rpc	X
test-fw-nrfconnect-rs	X
test-fw-nrfconnect-thread	X
test-low-level	X
test-sdk-find-my	X

Detailed information of selected test modules

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[NordicBuilder]

You can find the documentation preview for this PR at this link. It will be updated about 10 minutes after the documentation build succeeds.

Note: This comment is automatically posted by the Documentation Publishing GitHub Action.

[nordic-segl]

Solution proposed by Maciej Perkowski was merged instead.