Remove cweagans/composer-patches from composer.json

We do need it in our dev dependencies because we apply patches to some dev-only stuff, but I agree -- this should not be in the top-level project template anymore.

Wait a minute...this is already done.

There is no mention of cweagans/composer-patches in https://git.drupalcode.org/project/drupal_cms/-/blob/1.x/project_templat..., which is what real projects will be spun up from.

The only mention of that plugin is in https://git.drupalcode.org/project/drupal_cms/-/blob/1.x/dev.composer.js..., which is used only for internal development and never exposed to end users in any way. (Unless they git clone the repo and spin up with that, which we explicitly say not to do in https://git.drupalcode.org/project/drupal_cms/-/blob/1.x/README.md?ref_t..., and on our project page, but I guess I can't force people to RTFM.

Closing since this is working as intended.