west.yml: MCUboot synchronization from upstream

Update Zephyr fork of MCUboot to revision:
  461e060e8687c9a75074effcc61d7f68c5112cfd

Brings following Zephyr relevant fixes:

  - 461e060e zephyr: Improve SHA support selectors
  - b9ba2573 boot: zephyr: kconfig: Default to swap using offset
  - cc8f6aff boot: zephyr: Set prefer swap using move for aligned
    boards
  - 37bc4aa4 zephyr: boards: nrf54h20dk: disable power domains
  - 5a728be9 boot: zephyr: Add support for Cortex-R cleanup before
    final jump
  - 83e2f934 boot: zephyr: Add Cortex-R support
  - c136f4a8 boot: zephyr: Remove references to tinycrypt
  - 3bf79cbc boot: zephyr: Remove support for deprecated LED dts
  - 3e02536f boot: bootutil: declare fih_panic_loop() as noreturn
  - 5eaf190a boot: zephyr: RAM cleanup debug loop
  - ecf01da3 zephyr: Add zephyr samples folder to list of samples
  - 724a7514 boot: zephyr: boards: Reformat DTS files
  - f9db0194 bootutil: Unify app_max_size() implementations
  - 6ea7add6 zephyr: Remove legacy flash_area_get_sectors
  - 7271062e boot: zephyr: boards: Remove outdated nrf54l15pdk
    board config
  - 5ce11a3b zephyr: boards: nrf - remove redundant multithreading
    configuration
  - fa4ca87a mbedtls: Move local mbedtls to v3.6.0
  - a736efa7 boot: zephyr: add support for revert mode with ramload
  - 61c5547b boot: zephyr: add ram_load overlays for nrf52840dk and
    mimxrt1050_evk boards

Signed-off-by: Jamie McCrae <jamie.mccrae@nordicsemi.no>