fix(lib/vscode): update csp in webview to allow ports

[jsjoeio]

With #3895, we caused a regression where the Content-Security-Policy prevented
images in the previewer to not work due to the ports in the resource URI.

This modifies the CSP in the webview to make sure images are not blocked by CSP.

I assume once we upgrade VS Code, we will revert this change.

Screeshot

See notes here: #3936 (comment)

Fixes #3936 #4098

TODOs

• test locally and see if this also fixes vsix extensions that utilise webviews are blocked by CSP #4098

Looks like this PR is a two-for-one!

[codecov]

Codecov Report

Merging #4131 (592d9bc) into main (8a1c129) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #4131   +/-   ##
=======================================
  Coverage   64.12%   64.12%           
=======================================
  Files          36       36           
  Lines        1873     1873           
  Branches      379      379           
=======================================
  Hits         1201     1201           
  Misses        571      571           
  Partials      101      101           

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[github-actions]

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