core: frontend: vehicle-setup: failsafes: disable unused parameters

[ES-Alexander]

Current behaviour

From #2748, the interface is consistent whether a failsafe is configured to do something or as disabled. This isn't specifically problematic, but it could be more intuitive if there was visual feedback about which failsafes are 'active'.

Expected or desired behaviour

Setup parameters for a failsafe (and possibly the whole failsafe card) should be greyed out and/or disabled when the corresponding failsafe Action is set to Disabled, with only the Action remaining interactive and with normal colours/shades. This would draw attention to that box, and make it more obvious that the other available parameters aren't actually having an effect when the relevant Action is not configured to do anything.

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Originally raised in this comment.

Prerequisites

• I have checked to make sure that a similar request has not already been filed or fixed.