update undici and tar to mitigate high risk vulnerbaility

[chunqilu]

Issue

Recent https://github.com/aws/code-editor/actions/runs/21270251703 reports that there are two high risk vulnerability,

• Undici, fixed version 7.18.2
• node-tar, fixed version 7.5.4

we need to mitigate them.

Description of Changes

This change

• updates undici to ^7.18.2 in package.json
• updates node-tar to ^7.5.4 by backport a vscode security fix microsoft/vscode@1deca73 which replaces gulp-untar with custom untar implementation and update dependencies. The change is made in original gulp js build script instead of first converting to ts as in microsoft/vscode@fcfb37c to minimize changes.

Testing

manual test locally

Screenshots/Videos

Additional Notes

Backporting

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