[Lens] Add confirmation modal for destructive layer actions

[MichaelMarcialis]

Per a recent conversation with @yuvielastic, Lens currently doesn't ask for user confirmation when attempting to use destructive layer actions (i.e. clear and delete). As such, he found himself in a position where he accidentally cleared his desired layer configuration with no way to get it back (as it hadn't been saved yet). While undo/redo functionality would be most desirable (as mentioned by @flash1293) and help prevent such situations, that is not a solution we are able to implement in the short-term.

Based on the above, and as we are planning to expand the number of available layer-level actions with future annotation enhancements, it may be a good interim solution to have a confirmation modal for the layer clear and delete actions. Within this proposed confirmation modal, we could also include an opt-out checkbox to never show the modal again for those users that understand the implications and don’t wish to be bothered by it again. I believe this may be a decent short-term compromise to prevent situations like the above, where folks are unclear as to what the button does, or the possibility of mis-clicks due to the proximity of other layer actions that will be added over time.

[elasticmachine]

Pinging @elastic/kibana-vis-editors @elastic/kibana-vis-editors-external (Team:VisEditors)

[mbondyra]

Not sure why this reopened. Closing.