Adds webp support to BaseImage with fallback

[stephiescastle]

Verifying strategy in other projects before finalizing this PR.

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Checklist

• Include a description of your pull request and instructions for the reviewer to verify your work.
• Link to the issue if this PR is issue-specific.
• Create/update the corresponding story if this includes a UI component.
• Create/update documentation. If not included, tell us why.
• List the environments / browsers in which you tested your changes.
• Tests, linting, or other required checks are passing.
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Description

Instructions to test

Tested in the following environments/browsers:

Operating System

• macOS
• iOS
• iPadOS
• Windows

Browser

• Chrome
• Firefox ESR
• Firefox
• Safari
• Edge