fix(ssr): transform superclass identifier

[bluwy]

Description

Following up on #13572, when transforming let foo = class extends Bar {}, the Bar is not transformed to the import used. Bar is considered a superclass in the AST.

Fixed the issue by checking if Bar is a class name id and not a superclass id.

Additional context

This is causing a fail in Astro's lit element test after transpiled by esbuild:

let MyElement = class extends LitElement {

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What is the purpose of this pull request?

• Bug fix
• New Feature
• Documentation update
• Other

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