fix: mode is not defined

[Morgbn]

Description

Import mode from '@chakra-ui/vue'

Motivation and Context

Fix #500

Codesandbox

Previously when using $mode in @chakra-ui/nuxt: https://codesandbox.io/s/nifty-monad-8lyvj?file=/pages/index.vue:409-543
Fixed: https://codesandbox.io/s/chakra-ui-nuxt-demo-forked-gxw0m?file=/pages/index.vue:409-543

[changeset-bot]

⚠️ No Changeset found

Latest commit: 0b3fa95

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[vercel]

This pull request is being automatically deployed with Vercel (learn more).
To see the status of your deployments, click below or on the icon next to each commit.

chakra-ui-vue – ./

🔍 Inspect: https://vercel.com/chakra-ui/chakra-ui-vue/7eb8zgdLgkpbf52sfNzCQ911i6qJ
✅ Preview: https://chakra-ui-vue-git-fork-morgbn-fix-mode-undefined-chakra-ui.vercel.app

[codesandbox-ci]

This pull request is automatically built and testable in CodeSandbox.

To see build info of the built libraries, click here or the icon next to each commit SHA.

Latest deployment of this branch, based on commit 0b3fa95:

Sandbox	Source
Chakra UI Vue (0.X) Starter Template	Configuration
chakra-ui-nuxt-demo	Configuration

[codebender828]

Thank you @Morgbn