Release: Prerelease 8.0.0-alpha.3

[github-actions]

This is an automated pull request that bumps the version from 8.0.0-alpha.2 to 8.0.0-alpha.3.
Once this pull request is merged, it will trigger a new release of version 8.0.0-alpha.3.
If you're not a core maintainer with permissions to release you can ignore this pull request.

To do

Before merging the PR, there are a few QA steps to go through:

• Add the "freeze" label to this PR, to ensure it doesn't get automatically forced pushed by new changes.
• Add the "ci:daily" label to this PR, to trigger the full test suite to run on this PR.

And for each change below:

1. Ensure the change is appropriate for the version bump. E.g. patch release should only contain patches, not new or de-stabilizing features. If a change is not appropriate, revert the PR.
2. Ensure the PR is labeled correctly with one of: "BREAKING CHANGE", "feature request", "bug", "maintenance", "dependencies", "documentation", "build", "unknown".
3. Ensure the PR title is correct, and follows the format "[Area]: [Summary]", e.g. "React: Fix hooks in CSF3 render functions". If it is not correct, change the title in the PR.
   • Areas include: React, Vue, Core, Docs, Controls, etc.
   • First word of summary indicates the type: “Add”, “Fix”, “Upgrade”, etc.
   • The entire title should fit on a line

This is a list of all the PRs merged and commits pushed directly to next, that will be part of this release:

• 🐛 Bug: Addon-docs: Fix storybook MDX check #24696
• 🐛 Bug: Blocks: Fix Subtitle block for unattached docs pages #25157 (will also be patched)
• 🔧 Maintenance: Maintenance: Set engines field to Node.js >= 18 for packages #25105
• 🔧 Maintenance: Addons: Remove unused postinstall package #25150
• 🐛 Bug: Ember: Fix @storybook/ember #23435
• 🐛 Bug: Angular: Update Angular cli templates #25152 (will also be patched)
• 🏗️ Build: Sandboxes: Use yarn1 for sandbox generation #25171

If you've made any changes doing the above QA (change PR titles, revert PRs), manually trigger a re-generation of this PR with this workflow and wait for it to finish. It will wipe your progress in this to do, which is expected.

Feel free to manually commit any changes necessary to this branch after you've done the last re-generation, following the Make Manual Changes section in the docs, especially if you're making changes to the changelog.

When everything above is done:

• Merge this PR
• Follow the run of the publish action

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Generated changelog

8.0.0-alpha.3

• Addon-docs: Fix storybook MDX check - #24696, thanks @ shilman!
• Addons: Remove unused postinstall package - #25150, thanks @ shilman!
• Angular: Update Angular cli templates - #25152, thanks @ Marklb!
• Blocks: Fix Subtitle block for unattached docs pages - #25157, thanks @ kripod!
• Ember: Fix @storybook/ember - #23435, thanks @ francois2metz!
• Maintenance: Set engines field to Node.js >= 18 for packages - #25105, thanks @ valentinpalkovic!