Deduplicate wasm binary in distribution

**Describe the bug**

`ffmpeg.wasm v0.12.1`

The wasm binary is duplicated into both `esm` and `umd` folders, inside `core/dist` making the final binary unnecessarily larger.

It would be great if we could consolidate these two, and have the js files reference them in the parent.

```console
(core/dist)$ tree -sh
[4.0K] .
├── [4.0K] esm
│ ├── [107K] ffmpeg-core.js
│ └── [ 30M] ffmpeg-core.wasm
└── [4.0K] umd
├── [107K] ffmpeg-core.js
└── [ 30M] ffmpeg-core.wasm

(core/dist)$ sha256sum esm/ffmpeg-core.wasm
5577137bc744cd19d1a0a12aa0d1b7ca314ad8e514e616c59f1428f60afdf059 esm/ffmpeg-core.wasm

(core/dist)$ sha256sum umd/ffmpeg-core.wasm
5577137bc744cd19d1a0a12aa0d1b7ca314ad8e514e616c59f1428f60afdf059 umd/ffmpeg-core.wasm
```

Observed this while updating dependencies that got bundled into a docker image. Seeing a near-50% increase in uncompressed image size. https://github.com/miraclx/freyr-js/pull/546