Added Firefox support for making Order Summary sticky when not longer than view

[wavvves]

Submission Review Guidelines:

• I have followed the WooCommerce Contributing Guidelines and the WordPress Coding Standards.
• I have checked to ensure there aren't other open Pull Requests for the same update/change.
• I have reviewed my code for security best practices.
• Following the above guidelines will result in quick merges and clear and detailed feedback when appropriate.

Changes proposed in this Pull Request:

Changes shipped on #47680 make use of computedStyleMap which is not supported in Firefox
This PR prevents the console errors and ads support for Firefox by using getComputedStyles.

Closes #49525

How to test the changes in this Pull Request:

Using the WooCommerce Testing Instructions Guide, include your detailed testing instructions:

1. On Firefox add a product to the Cart
2. Go to the Checkout Blocks page and open the inspector
3. Verify the following error is not displayed in the JS console Uncaught TypeError: e.computedStyleMap is not a function...
4. Reduce the window height so that it's smaller than the order summary.
5. Try scrolling, the order summary should not be sticky.
6. Collapse the items in order summary and expand the window height.
7. Try scrolling now, the order summary should be sticky.

Verify everything still works on other supported browsers by following steps:

1. Add some items to cart and go to Checkout.
2. Reduce the window height so that it's smaller than the order summary.
3. Try scrolling, the order summary should not be sticky.
4. Collapse the items in order summary and expand the window height.
5. Try scrolling now, the order summary should be sticky.

Changelog entry

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Changelog Entry Details

Significance

• Patch
• Minor
• Major

Type

• Fix - Fixes an existing bug
• Add - Adds functionality
• Update - Update existing functionality
• Dev - Development related task
• Tweak - A minor adjustment to the codebase
• Performance - Address performance issues
• Enhancement - Improvement to existing functionality

Message

Changelog Entry Comment

Comment

[github-actions]

Hi @senadir, @woocommerce/rubik

Apart from reviewing the code changes, please make sure to review the testing instructions and verify that relevant tests (E2E, Unit, Integration, etc.) have been added or updated as needed.

You can follow this guide to find out what good testing instructions should look like:
https://github.com/woocommerce/woocommerce/wiki/Writing-high-quality-testing-instructions

[github-actions]

Test using WordPress Playground

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Test this pull request with WordPress Playground.

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[github-actions]

Size Change: +39 B (0%)

Total Size: 2.3 MB

_{compressed-size-action}

[senadir]

Works as expected, thank you!