Content Only mode should allow controls in the Inspector to still be reachable if they are content related

[fabiankaegy]

We have more and more controls that I would consider content rather than design tools that are only visible in the Inspector controls of a block. Currently however the content only mode hides the blocks inspector controls entirely.

This is a major issue for things like the Alt text of the image block which cannot be changed in the context of a content only mode.

But also new other tools such as the background image option on the group block, or the rel attribute for buttons, anchor tags for elements etc are common pieces of content that should be editable in the content only mode.

I think with the introduction of the useBlockEditingMode we have a robust API to make granular choices about which settings should display in the content only mode and we should therefore rethink the limitation of disabling the inspector all together for content only locking.

gutenberg/packages/block-editor/src/components/block-inspector/index.js

Lines 171 to 177 in aec6947

	if ( topLevelLockedBlock ) {
	return (
	<BlockInspectorLockedBlocks
	topLevelLockedBlock={ topLevelLockedBlock }
	/>
	);
	}

[fabiankaegy]

CC: @annezazu @SaxonF this is what I referenced in our Hallway Hangout yesterday.

And @talldan because we talked about this in #53705 (comment)

[talldan]

Thanks! I've referenced this in the TODO list of the pattern overrides tracking issue.

[fabiankaegy]

Just noting here that a workaround was found for the image blocks alt text in #58998 🎉