Don't allow setting Meta of={X} if X is tagged with 'autodocs'

[tmeasday]

Telescoping on #20364

What I did

Throw an error if you use <Meta of={} for autodocs-tagged CSF file.

I'm not 100% sure this should be an error while other "mistakes" are just warnings. WDYT @shilman?

storybook/code/lib/core-server/src/utils/StoryIndexGenerator.ts

Lines 364 to 399 in 2f713e5

	// This shouldn't be possible, but double check and use for typing
	if (worseEntry.type === 'story')
	throw new DuplicateEntriesError(`Duplicate stories with id: ${firstEntry.id}`, [
	firstEntry,
	secondEntry,
	]);
	if (betterEntry.type === 'story') {
	const worseDescriptor = worseEntry.standalone
	? `component docs page`
	: `automatically generated docs page`;
	if (betterEntry.name === this.options.docs.defaultName) {
	logger.warn(
	`🚨 You have a story for ${betterEntry.title} with the same name as your default docs entry name (${betterEntry.name}), so the docs page is being dropped. Consider changing the story name.`
	);
	} else {
	logger.warn(
	`🚨 You have a story for ${betterEntry.title} with the same name as your ${worseDescriptor} (${worseEntry.name}), so the docs page is being dropped. ${changeDocsName}`
	);
	}
	} else if (betterEntry.standalone) {
	// Both entries are standalone but pointing at the same place
	if (worseEntry.standalone) {
	logger.warn(
	`🚨 You have two component docs pages with the same name ${betterEntry.title}:${betterEntry.name}. ${changeDocsName}`
	);
	}
	// If you link a file to a tagged CSF file, you have probably made a mistake
	if (worseEntry.tags?.includes('autodocs'))
	throw new Error(
	`You created a component docs page for ${betterEntry.title}:${betterEntry.name}, but also tagged the CSF file with 'autodocs'. This is probably a mistake.`
	);
	// Otherwise the existing entry is created by `autodocs=true` which allowed to be overridden.
	} else {

How to test

• Create a MDX file with <Meta of={..} an autodocs-tagged CSF File.
• Check it doesn't break in other allowed circumstances (no tag, or autodocs=true)

[shilman]

@tmeasday We have another issue to make index errors crash Storybook so I think this is in line with that direction