fix(legacy): restore entry chunk CSS inlining, reverts #9761

[sapphi-red]

Description

When an entry chunk is imported by dynamic import, the CSS wasn't loaded in legacy mode.

fixes #10285
refs #10185
reverts #9761

Additional context

#10285 (comment)

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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