[Fix] nvm : Check if Node version is already active before switching

[adssib]

Description:

This PR adds a check to ensure that nvm doesn't attempt to switch to a Node.js version if it's already the active version. If the user tries to use a version that's already active, the script will print a message and skip the redundant operation, improving efficiency and user experience.

Changes:

Added a check using nvm current to compare the currently active version with the requested version.
If the requested version is already active, it prints a message and exits without switching versions.

Issues:

Related to issue: #3545

[ljharb]

This only covers nvm exec, not nvm use, and results in the user’s command not executing, which will break things. There’s also no tests included.