fix(esbuild): exclude reveal.js marked plugin

https://github.com/hedgedoc/hedgedoc/pull/4114
did not properly fix the missing speaker notes.

It turns out that by just excluding
reveal.js/plugin/markdown/marked.js
from esbuild processing, we can stop invalid JS from being generated.

Signed-off-by: David Mehren <git@herrmehren.de>

webpack.prod.js

@@ -17,8 +17,8 @@ module.exports = [
       minimizer: [
         new EsbuildPlugin({
           target: 'es2015',
-          format: "cjs",
-          exclude: ['MathJax/extensions/a11y/mathmaps']
+          format: 'cjs',
+          exclude: ['MathJax/extensions/a11y/mathmaps', 'reveal.js/plugin/markdown/marked.js']
         })
       ],
       splitChunks: {
@@ -33,7 +33,7 @@ module.exports = [
       minimizer: [
         new EsbuildPlugin({
           target: 'es2015',
-          format: "cjs"
+          format: 'cjs'
         }),
         new OptimizeCSSAssetsPlugin({})
       ]