Build: Use --follow-symlinks in VSCE

[JustinGrote]

Prerequisites

• I have written a descriptive issue title.
• I have searched all issues to ensure it has not already been reported.

Summary

vsce as of October now (finally) supports symlink following, so our build scripts can stop the dumb task of copying PSES to vscode for a build.

microsoft/vscode-vsce@51e122a

Proposed Design

No response

[SydneyhSmith]

@andyleejordan says go for it 😄

[JustinGrote]

Thanks @andyleejordan!