enhancement(vscode): error handling when download plugins

[gaocegege]

Description

When we get an invalid plugin, the download also works but the visix content may be:

{"$id":"1","innerException":null,"message":"The extension 'dbaeumer.vscode-eslint' doesn't contain the requested version '1.1.1'.","typeName":"Microsoft.VisualStudio.Services.Gallery.WebApi.ExtensionVersionNotFoundException, Microsoft.VisualStudio.Services.Gallery.WebApi","typeKey":"ExtensionVersionNotFoundException","errorCode":0,"eventId":3000}%   

Then the code panics because we want to unzip such a file.

We need to have better error handling in this situation.