Specify core-js@3.28.0 and update webdatastreams.js to use toSorted with polyfill imported.

[benbowler]

Summary

Addresses issue:

• Update Babel Configuration to Support toSorted() Method #7571

Relevant technical choices

As suggested by @techanvil using core-js by specifying version 3.28.0 allows us to use toSorted in the tests.

PR Author Checklist

• My code is tested and passes existing unit tests.
• My code has an appropriate set of unit tests which all pass.
• My code is backward-compatible with WordPress 5.2 and PHP 5.6.
• My code follows the WordPress coding standards.
• My code has proper inline documentation.
• I have added a QA Brief on the issue linked above.
• I have signed the Contributor License Agreement (see https://cla.developers.google.com/).

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Code Reviewer Checklist

• Run the code.
• Ensure the acceptance criteria are satisfied.
• Reassess the implementation with the IB.
• Ensure no unrelated changes are included.
• Ensure CI checks pass.
• Check Storybook where applicable.
• Ensure there is a QA Brief.

Merge Reviewer Checklist

• Ensure the PR has the correct target branch.
• Double-check that the PR is okay to be merged.
• Ensure the corresponding issue has a ZenHub release assigned.
• Add a changelog message to the issue.

[github-actions]

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[github-actions]

Size Change: +7.36 kB (0%)

Total Size: 1.49 MB

Filename	Size	Change
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ℹ️ View Unchanged

Filename	Size
./dist/assets/css/googlesitekit-admin-css-********************.min.css	50.8 kB
./dist/assets/css/googlesitekit-adminbar-css-********************.min.css	11.1 kB
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./dist/assets/js/34-********************.js	3.12 kB
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./dist/assets/js/googlesitekit-polyfills-********************.js	379 B

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