fix(cli.rs): prefix the "before script" env vars with TAURI_

[JonasKruckenberg]

Before we exported env vars to the "before scripts" (beforeDevCommand and beforeBuildCommand) like this ARCH, PLATFORM and VERSION which is problematic for two reasons:

1. It can clash with env variables defined by the OS (ARCH is very generic for example)
2. It wasn't clear that the env vars above came from the tauri bundling process.
3. Tools like vite, have a whitelist by prefix for security reasons. So having everything prefixed with TAURI_ will make life easier and more secure for our tauri+vite users.

What kind of change does this PR introduce?

• Bugfix
• Feature
• Docs
• New Binding issue #___
• Code style update
• Refactor
• Build-related changes
• Other, please describe:

Does this PR introduce a breaking change?

• Yes, and the changes were approved in issue #___
• No

Checklist

• When resolving issues, they are referenced in the PR's title (e.g fix #___, #___)
• A change file is added if any packages will require a version bump due to this PR per the instructions in the readme.
• I have added a convincing reason for adding this feature, if necessary

Other information

[FabianLars]

Good idea imo

[JonasKruckenberg]

Good idea imo

I caused the problem, I fix the problem lol 😂