[Canvas] Display settings for all elements in a group

[ryankeairns]

Describe the feature:
As a user, I would like to change the settings for an element when it is part of a group without having to ungroup it first.

Describe a specific use case for the feature:
If I group a set of elements into a single unit then I shouldn't have to always ungroup it before I can edit any of those items. For example, to change the color of a shape, text styles, a SQL query, or an expression.

This becomes more evident when inserting a custom, user-defined element (aka element template). In the initial version of element templates #25531 , we are going to show a message that instructs a user to ungroup before editing. This improves that experience and keeps that grouped element intact.

Mockup / suggested side panel for a grouped element

[elasticmachine]

Pinging @elastic/kibana-canvas

[shaunmcgough]

@ryankeairns Could I close this in favor of #35907

[ryankeairns]

@shaunmcgough done, closed it.