Prompted by https://github.com/pulumi/pulumi-yaml/pull/546
At some point we added `__logicalName` to outputs to match
resources/config. But outputs don't actually need lexical and logical
names, they only have logical names. In the cases where `__logicalName`
was set the lexical name was totally ignored.
We can simply just use the block label (block labels can be arbitrary
strings) and eventually deprecate the `__logicalName` option on
`output`.