fix escaping of sigils in SSR non-top-level <script> and <style>

[Conduitry]

Oversight in my PR for #1082. We should also make sure to cover this in #1087 once that test is working.

[codecov-io]

Codecov Report

Merging #1097 into master will not change coverage.
The diff coverage is 0%.

@@           Coverage Diff           @@
##           master    #1097   +/-   ##
=======================================
  Coverage   91.56%   91.56%           
=======================================
  Files         123      123           
  Lines        4493     4493           
  Branches     1447     1447           
=======================================
  Hits         4114     4114           
  Misses        162      162           
  Partials      217      217

Impacted Files	Coverage Δ
...nerators/server-side-rendering/visitors/Element.ts	84.84% <0%> (ø)	⬆️

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