sysbuild: Set CONFIG_SOFTDEVICE on applications when it is enabled

[nordicjm]

The application Kconfigs seem to have been changed, therefore force setting this Kconfig on when it is enabled by sysbuild

[github-actions]

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[anhmolt]

I'm able to fix the failing samples bm_zms_rram and storage_rram by adding SB_CONFIG_SOFTDEVICE_NONE=y to the extra_args: in sample.yaml of these sample variants. But this raises the question weather reintroducing non-SoftDevice boards would be preferable.

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