fix: undefined parent_component in Component.ts

[pierre-cm]

This change fixes an issue in Component.ts where an error occurs when the parent_component parameter is undefined, causing the following error: "Cannot read properties of undefined (reading '$$')".

The proposed solution is to add a null check to the parent_component parameter before accessing the $$ property.

This change ensures that the code works even when parent_component is not defined, as is the case when importing a module dynamically.

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

• It's really useful if your PR references an issue where it is discussed ahead of time. In many cases, features are absent for a reason. For large changes, please create an RFC: https://github.com/sveltejs/rfcs
• Prefix your PR title with feat:, fix:, chore:, or docs:.
• This message body should clearly illustrate what problems it solves.
• Ideally, include a test that fails without this PR but passes with it.

Tests

• Run the tests with npm test and lint the project with npm run lint

[vercel]

@pierre-cm is attempting to deploy a commit to the Svelte Team on Vercel.

A member of the Team first needs to authorize it.

[vercel]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Comments	Updated
svelte-dev-2	❌ Failed (Inspect)			Feb 22, 2023 at 0:41AM (UTC)

[benmccann]

Can you share a reproduction of the issue this is fixing?

[dummdidumm]

Closing as duplicate of #6646. In general we very likely won't make this change, see #6584 (comment) for the "why".