chore: Remove unwanted case

[jeevithakannan2]

Type of Change

• [ ] New feature
• [ ] Bug fix
• [ ] Documentation update
• [x] Refactoring
• [ ] Hotfix
• [ ] Security patch
• [ ] UI/UX improvement

Description

• Unsupported package manager is already handled in common-script.sh https://github.com/ChrisTitusTech/linutil/blob/26d0adc829ac59893666559f1c126d05b7fddc6b/core/tabs/common-script.sh#L86
• Removed pacman from linutil-installer.sh cargo installation section as pacman case is already handled.
• Remove snaps script is excluded as it may conflict with #756

Testing

• No errors works as expected.

Checklist

• [x] My code adheres to the coding and style guidelines of the project.
• [x] I have performed a self-review of my own code.
• [x] I have commented my code, particularly in hard-to-understand areas.
• [ ] I have made corresponding changes to the documentation.
• [x] My changes generate no errors/warnings/merge conflicts.