userDataBase64 not respected for AutoScalingLaunchConfiguration

[JoseAlban]

See

pulumi-awsx/awsx-classic/autoscaling/launchConfiguration.ts

Line 62 in 5f3b5d4

userData: getInstanceUserData(args, this.stackName),

This merges args which might contain userDataBase64 with a userData that's created even if undefined provided, and yields error like:

aws:ec2:LaunchConfiguration (local-launchcfg-general-purpose):
    error: aws:ec2/launchConfiguration:LaunchConfiguration resource 'local-launchcfg-general-purpose' has a problem: "user_data": conflicts with user_data_base64
    error: aws:ec2/launchConfiguration:LaunchConfiguration resource 'local-launchcfg-general-purpose' has a problem: "user_data_base64": conflicts with user_data

...because LC can't have both - so awsx made the userdatabase64 unusable.