Global time range on Dashboards should be rounded

[thomasneirynck]

note this is a duplicate of #94280. It might be useful to track its impact on Dashboards specifically.

Time ranges are not rounded. This creates timestamps with ms precision. This prevents related contexts to share the same timerange (e.g. adding a filters in quick succession, navigating to and from a Dashboard, ...). Having consistent time-ranges are important because they better leverage query-caching on the Elasticsearch side.

Not entirely sure whether this is the responsibility of Dashboards/Embeddable system, rather than an issue with the individual widgets not performing the rounding (e.g. this is a Lens/Maps issue). Either way, rounding should occur. Since we likely want to have consistent date-ranges within each Dashboard context, my hunch is that the Embeddable system/Dashboarding should enforce rounding.

[elasticmachine]

Pinging @elastic/kibana-presentation (Team:Presentation)

[ThomThomson]

I've been considering adding a rounding option to the Dashboard itself - which would allow authors to specify the amount of rounding, because IMO authors are the only people that know how accurate their data must be to be useful.

We would then just need to choose an appropriate default.

[thomasneirynck]

duplicate of #94280.