Allowed attribute string value edge cases

[mattrosno]

Description

Tell us more about the problem that you're running into. What did you see? What did you expect to see?

This likely needs broken down into more issues, but when running the config generator against this repo, here is the manual cleanup that I had to do:

https://github.com/carbon-design-system/carbon-addons-iot-react/pull/3854/commits/ec74fd5f438c9b63b629c38ecce139477f22453d

• [ ] Double quotes

Some values had double quotes, e.g.:

        - '"lg"'
        - '"max"'
        - '"md"'
        - '"sm"'
        - '"xl"'
        - '"xs"'

• [ ] Prop types

I was surprised to see prop types as valid values, e.g.:

        - |-
          PropTypes.shape({
            peak: PropTypes.number,
            meterTotal: PropTypes.number,
            meterUnit: PropTypes.string,
            totalFormatter: PropTypes.func,
            legendPosition: PropTypes.string,
            ...ChartColorPropType,
          })

• [ ] Empty strings

There were a few empty strings that shouldn't have been there? Maybe these are okay, if it's value to set a prop with an empty string.

        - ''

• [ ] Object.values

I'm guessing we don't want executable JS as valid values? E.g.:

        - ...Object.values(ITEM_VALUE_KEYS)

Steps to reproduce

How do we reproduce the error? Please be as specific as you can.

1. https://github.com/carbon-design-system/carbon-addons-iot-react/pull/3854/commits/ec74fd5f438c9b63b629c38ecce139477f22453d

[mattrosno]

@francinelucca here's another example. Nothing net new beyond what's already documented in this issue: https://github.ibm.com/ibmcloud/cloud-pal-community/pull/562/commits/386d5f90cd2c9b8f2e2594745c631e2c9923db76