Don't go to the ext host for default terminal shell/args in tasks

[Tyriar]

I noticed this call here which goes to the exthost:

vscode/src/vs/workbench/contrib/tasks/browser/terminalTaskSystem.ts

Line 1024 in 2e2dc15

defaultConfig = await variableResolver.taskSystemInfo.getDefaultShellAndArgs();

It seems to be the only usage of that proxy call, you can now call this on the renderer for the same thing:

ITerminalProfileResolverService.getDefaultProfile({
  os: terminalBackendOS, // probably remoteAgentService.getEnvironment().os || OS
  remoteAuthority: terminalBackendRemoteAuthority,
  allowAutomationShell: true
});