Description

This #6340 introduced changes to the definePlugin that broke ecosystem-ci tests of 2.9-beta for svelte due to changes how it replaces import.meta.env.SSR

see https://discord.com/channels/804011606160703521/949170949117313085

Steps to take:

• add a testsuite that ensures import.meta.env replacements are working as expected
• rollback the og change pr to get them passing
• discuss what kind of changes/improvements we want to make in 2.9

Additional context

What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

Before submitting the PR, please make sure you do the following

• Read the Contributing Guidelines.
• Read the Pull Request Guidelines and follow the Commit Convention.
• Check that there isn't already a PR that solves the problem the same way to avoid creating a duplicate.
• Provide a description in this PR that addresses what the PR is solving, or reference the issue that it solves (e.g. fixes #123).
• Ideally, include relevant tests that fail without this PR but pass with it.