Update global pnpm Preflight installation command

[ProchaLu]

Description

This PR updates the installation command for the pnpm package manager's global Preflight installation. The current installation command is pnpm global add @upleveled/preflight, but this PR changes it to pnpm add --global @upleveled/preflight. This change aligned with the recommended installation process for pnpm packages.

Running the command without creating global-bin-dir with pnpm setup throws an error

ERR_PNPM_NO_GLOBAL_BIN_DIR Unable to find the global bin directory

Todo

• [ ] Research pnpm setup
• [x] Complete the changes after testing pnpm add --global @upleveled/preflight on Windows and Linux to see how pnpm behaves there

[karlhorky]

Maybe you can also do a PR for Preflight: https://github.com/upleveled/preflight

[karlhorky]

Seems like the ERR_PNPM_NO_GLOBAL_BIN_DIR issue is indeed still a problem on a fresh Linux (Ubuntu) installation:

• https://github.com/upleveled/system-setup/issues/58