fix: __DEV__ build conflict (fix #221)

[briangleeson]

Issue: #221

Using __DEV__ in a few places causes error during production build if another package also uses that variable name, as the build replaces __DEV__ with false in the other package. Renaming the variable used in vite-ssr avoids this conflict

For example, see this error:

[commonjs--resolver] Unexpected keyword 'false' (55:5) in C:/Snaps/pwp/pwp-ui/node_modules/@carbon/react/es/components/ModalWrapper/ModalWrapper.js
file: node_modules/@carbon/react/es/components/ModalWrapper/ModalWrapper.js:55:5
55:   if(false) {

[briangleeson]

@frandiox would it be possible to get this reviewed? We're eager to get this issue fixed and available in a new release of vite-ssr

[briangleeson]

@m3hari you appear to have merged changes in this repo in the past, would you be able to review this PR? There's no sign of @frandiox

[frandiox]

Hey @briangleeson ! Sorry I've out of town for a while 😓 -- I'll try to merge this and release but will probably need to be next week.

[briangleeson]

Ok, that'd be great 👍