fix(csp): remove inoperative self token from sandboxed html preview img-src

Author: waleedlatif1

apps/sim/app/workspace/[workspaceId]/files/components/file-viewer/preview-panel.tsx

@@ -734,7 +734,7 @@ const HTML_PREVIEW_CSP = [
   "default-src 'none'",
   "script-src 'unsafe-inline'",
   "style-src 'unsafe-inline'",
-  "img-src 'self' https: data: blob:",
+  'img-src https: data: blob:',
   'font-src data:',
   'media-src data: blob:',
   "connect-src 'none'",