ability to hide block actions

[nielslyngsoe]

Appends a Observable and methods to hide/show actions on Blocks.

They are shown by default, but this enables a custom view to consume Block Entry Context to then hide the actions.

[Copilot]

Pull Request Overview

This PR introduces a new observable flag to control the visibility of block action bars and updates various block entry components to respect this setting.

• Adds actionsVisibility state and hideActions/showActions methods to the block entry context.
• Updates RTE, list, and grid entry components to observe the new context flag and conditionally render their action bars.
• Refactors inline action-bar markup into #renderActionBar methods for each component.

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
block-entry.context.ts	Added #actionsVisibility state and visibility toggle methods.
block-rte-entry.element.ts	Introduced _showActions state, observation, and refactored action-bar rendering.
block-list-entry.element.ts	Similar updates for list entries: _showActions and #renderActionBar.
block-grid-entry.element.ts	Same enhancements for grid entries with conditional rendering of action bar.

[madsrasmussen]

Could it make sense to use a guard to align concepts? Instead of just a boolean, could we set up an UmbBlockActionsViewGuard? 🤔