blurDataURL inflates bundle even when not used

### Verify canary release - [X] I verified that the issue exists in the latest Next.js canary release ### Provide environment information ```bash Operating System: Platform: linux Arch: x64 Version: #1 SMP PREEMPT_DYNAMIC Sun Aug 6 20:05:33 UTC 2023 Binaries: Node: 16.17.0 npm: 8.15.0 Yarn: 1.22.19 pnpm: 7.1.0 Relevant Packages: next: 13.4.15-canary.0 eslint-config-next: N/A react: 18.2.0 react-dom: 18.2.0 typescript: 5.1.3 Next.js Config: output: N/A ``` ### Which area(s) of Next.js are affected? (leave empty if unsure) Image optimization (next/image, next/legacy/image) ### Link to the code that reproduces this issue or a replay of the bug https://codesandbox.io/p/sandbox/tender-morning-84653l ### To Reproduce Import a large image into any page while image optimization is enabled for the project. For extra points, and extra bundle bloat, import an animated image. Use the image with `next/image`, but do not enable the blur placeholder. Build the project and inspect the JS bundle for the page the image is used on. ### Describe the Bug The Webpack loader for images in Next.js *always* injects a blurDataURL into the JS bundle, even if it is unused in the code. It looks like in 13.4.8 some sort of tree-shaking was added that makes this no longer an issue for the native image tag, but this is still a problem for `next/image`. For large images, and especially animated images where the "blur" image is just the original image, this massively inflates the JS bundle. There does not appear to be a way to opt-out of this blurDataURL being generated for a specific image, unless you opt the entire project out of using the image optimization, which means without this being tree-shaken correctly, there is no way to escape this bundle inflation if you want to use `next/image`. https://github.com/vercel/next.js/blob/c4f9c6d492d5daf3b470a755eaf3d0f68dd0df08/packages/next/src/build/webpack-config…