make the button component accept a label prop, (not children) (used for sandboxes and renderAssets in cli)

[ndelangen]

fix the pending changes in chromatic on the vue sandboxes
the pending changes are actually wrong, this should fix that.

I made it so we consistently use the label prop to insert text in the button, rather than a children prop.
The idea behind this is that this is accurate enough and renderer agnostic.

[ndelangen]

🤹‍♂️ Generating repros with a concurrency of 1
⚙️ Starting local registry: http://localhost:[6](https://github.com/storybookjs/storybook/actions/runs/3236765830/jobs/5303009844#step:7:7)001
> CI=true yarn local-registry --open
> yarn wait-on http://localhost:6001
🌏 found a open port: 6001
📐 reading version of storybook
🚛 listing storybook packages
🎬 starting verdaccio (this takes ±5 seconds, so be patient)
 warn --- Verdaccio started
 warn --- Plugin successfully loaded: verdaccio-auth-memory
🧬 generating Create React App (Javascript)
🌿 verdaccio running on http://localhost:6001
👤 add temp user to verdaccio
📦 found 81 storybook packages at version [7](https://github.com/storybookjs/storybook/actions/runs/3236765830/jobs/5303009844#step:7:8).0.0-alpha.35
📦 Configuring local registry: http://localhost:6001
🎁 Installing storybook
📦 Restoring registry: https://registry.npmjs.org/
🧬 generating Create React App (Typescript)
(node:247[8](https://github.com/storybookjs/storybook/actions/runs/3236765830/jobs/5303009844#step:7:9)) UnhandledPromiseRejectionWarning: Error: Command failed with exit code 1: /home/runner/work/storybook/storybook/code/lib/cli/bin/index.js init --yes
     Unable to find versions of storybook using yarn
     Unable to find versions of @storybook/react using yarn
     Unable to find versions of @storybook/react-webpack5 using yarn
     Unable to find versions of @storybook/addon-links using yarn
     Unable to find versions of @storybook/addon-essentials using yarn
     Unable to find versions of @storybook/addon-interactions using yarn
     Unable to find versions of @storybook/node-logger using yarn
error An unexpected error occurred: "http://localhost:6001/@storybook%2faddon-a11y: no such package available".
An error occurred while installing dependencies.
    at makeError (/home/runner/work/storybook/storybook/scripts/node_modules/execa/lib/error.js:60:11)
    at handlePromise (/home/runner/work/storybook/storybook/scripts/node_modules/execa/index.js:118:26)
    at runMicrotasks (<anonymous>)
    at processTicksAndRejections (internal/process/task_queues.js:[9](https://github.com/storybookjs/storybook/actions/runs/3236765830/jobs/5303009844#step:7:10)5:5)
    at async sbInit (/home/runner/work/storybook/storybook/scripts/next-repro-generators/generate-repros.ts:33:3)
    at async /home/runner/work/storybook/storybook/scripts/next-repro-generators/generate-repros.ts:64:7
    at async withLocalRegistry (/home/runner/work/storybook/storybook/scripts/next-repro-generators/generate-repros.ts:42:5)
    at async addStorybook (/home/runner/work/storybook/storybook/scripts/next-repro-generators/generate-repros.ts:61:5)
    at async /home/runner/work/storybook/storybook/scripts/next-repro-generators/generate-repros.ts:[14](https://github.com/storybookjs/storybook/actions/runs/3236765830/jobs/5303009844#step:7:15)1:9
(Use `node --trace-warnings ...` to show where the warning was created)
(node:2478) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 1)
(node:2478) [DEP00[18](https://github.com/storybookjs/storybook/actions/runs/3236765830/jobs/5303009844#step:7:19)] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.

[ndelangen]

allright, i think i got it!, finally

[tmeasday]

LGTM!