Fix bunx command for github package #5974

[axlEscalada]

What does this PR do?

Fix the bunx command when a github repo is passed as an argument. There is a bug where the package name is parsed as an UpdateRequest that leaves the name of the package empty and fails when trying to concatenate name + @ + version
In bunx_command name and version are checked and if they are equal set the name as the package name, and format it without @. Also this fmt package is used to build the path where is installed.

Fixes: #5974

• Documentation or TypeScript types (it's okay to leave the rest blank in this case)
• Code changes

How did you verify your code works?

• I checked the lifetime of memory allocated to verify it's (1) freed and (2) only freed when it should be
• I or my editor ran zig fmt on the changed files
• I included a test for the new code, or an existing test covers it
• JSValue used outside outside of the stack is either wrapped in a JSC.Strong or is JSValueProtect'ed

[Jarred-Sumner]

Thank you for this. One nitpicky comment

[Electroid]

Tested and good-to-go. Thanks!