YAML: Allow use of typed values (boolean & number) instead of requiring strings for everything

[emersonknapp]

Description

In a YAML launchfile, one must

include:
   ...
   if: "False"

even though the expected final substitution resolution is a boolean, and YAML has a boolean type.
It's opaque to users why this acts this way and adds friction to usage of the YAML frontend.
It would be more ergonomic to allow:

node:
    if: false

I believe this restriction comes from the legacy of XML being the original launch frontend, which doesn't have boolean and numeric types, really, though XSD schemas can check them the same way we do the strings that come in.

Motivation

Reduce friction for writers of YAML launchfiles. How many times have I done if: false or the like and had the launchfile fail to launch? Too many, what a waste of time.

Design / Implementation Considerations

No response

Additional Information

No response