Remove type: "commonjs" to fix importing in NextJS

[sjdemartini]

When "type": "commonjs" is specified in our package.json, it apparently causes the following problem in NextJS:

Module parse failed: 'import' and 'export' may appear only with 'sourceType: module' (1:0)
> export { default as ControlledBubbleMenu, } from "./ControlledBubbleMenu";
| export { default as LinkBubbleMenu, } from "./LinkBubbleMenu";
| export { default as MenuBar } from "./MenuBar";

This is odd, since we indeed are using "commonjs" type, as that's the default (https://nodejs.org/api/packages.html#type), but it seems that fortunately merely omitting this resolves import errors in NextJS, and still supports NodeJS, based on my testing.

Should resolve #264, removing one of the changes from #259, while still hopefully keeping #256 fixed.

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Note that I did try other approaches in attempting to fix NextJS and still support Node:

1. Using tsup/rollup again like Use tsup to build project compatible with CJS and ESM, and validate in CI #258, with @mui/icons-material bumped to v6 for supposed "proper" ESM support Project build fails with mui-tiptap v1.10.0: Module parse failed: 'import' and 'export' may appear only with 'sourceType: module' (1:0) #264 (comment), but that still caused problems in the Node context. It seems icons-material still doesn't use .js extensions, so is still not correct.
2. Switch to "type": "module", using .js extensions for all relative imports in the project (enforced/automated with the eslint plugin eslint-plugin-require-extensions). This seemed like an improvement, but still seems it would require some workarounds for lodash and/or mui/icons-material like in Use tsup to build project compatible with CJS and ESM, and validate in CI #258 in the Node context, as those imports of the third party dependencies failed when importing mui-tiptap.