Remove html2canvas from webpack config

[jna4k]

Description

We can remove the two mentions of html2canvas in buildConfig.js and createExtensionWebpackConfig.js they are no longer needed.

The html2canvas package was removed back in march with this PR #10959 and running npm explain html2canvas tells me that there are no traces left of the package.

What kind of improvement you want to add? (check one with "x", remove the others)

• Other... Please describe:

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