Remove additional request to check if error is UserCancelledError

### Is your feature request related to a problem? Please describe.

error && error.constructor && error.constructor.name !== 'UserCancelledError')
: this code is currently a no op I believe, and it should be removed. See dicussion at https://github.com/dotnet/vscode-dotnet-runtime/pull/1613#discussion_r1465974996.

### A clear and concise description of what you want to happen. Include any alternative solutions you've considered.

Remove it

### Describe the solution you'd like
I think the UserCancelledError type may not be accessible to us as it comes from external libraries and that's why I did it this way...

Actually looking at this further, this entire check seems unnecessary because that error should be wrapped by a DotnetInstallExpectedAbort type, so I'd expect this line of code to never run. Since this is vendor tested, I'm going to keep it in in the off chance it actually would break something, but I am going to open an issue for myself to remove it in the future: https://github.com/dotnet/vscode-dotnet-runtime/issues/1636
### Additional context

_No response_