[Discover][UnifiedHistogram] Remove exception preventing code when rendering the chart

[kertal]

In #200687 we added code, to prevent flakiness when the UnifiedHistogram was being rendered in Discover. It was clearly reproduceable, that the following action led to an exception when rendering the UnifiedHistogram which is using the Lens Embeddable.

• Install all sample data.
• On Discover page, create an ad hoc data view kib* with @timetamp as the time field.
• Edit data view and set timestamp as the time field.
• Edit again and remove the time field.
• Edit again and set timestamp as the time field.
• This caused the histogram to fail, but this should no longer be the case

The code added in #200687 was safeguarding the given exception, which appeared to be the most reliable of multiple approaches. But it didn't target the root cause, which appears to be a race condition in the way the required properties were passed in the component.

However it should be removed once possible, which could be done after a refactoring of the UnifiedHistogram or even when #186642 was merged (which refactors large parts of the code)

[elasticmachine]

Pinging @elastic/kibana-data-discovery (Team:DataDiscovery)

[jughosta]

Addressed via

• [8.17] [Discover] Address the flaky histogram code (#201809) #202117
• [8.16] [Discover] Address the flaky histogram code (#201809) #202116