enabling babel-loader cacheDirectory does not recognize new icons

If we enable the [`cacheDirectory` option of `babel-loader`](https://github.com/babel/babel-loader#options) changes to an icon do not trigger rebuilds of webpack 🤔

But changes in `.jsx`, `.js`, `.scss` etc. files do work even if `cacheDirectory` is enabled.

Reproduce the issue with webpack and babel-loader's cacheDirectory enabled, changing an SVG icon while comparing the behavior with JSX, JS, and SCSS changes. Trace how the plugin and webpack detect SVG dependencies. Done means icon changes trigger webpack rebuilds without breaking the existing rebuild behavior for other file types.

Written by the indexing model from the issue text.