drive-by: remove timeout in selfXSS dialog for SourceFrames, because
this hack is not needed anymore.

Fixed: 513762734
Change-Id: I7b4106f0ed0de88ed630eab66f6eb4eebe10326b
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/7849088
Commit-Queue: Wolfgang Beyer <wolfi@chromium.org>
Reviewed-by: Natallia Harshunova <nharshunova@chromium.org>