Unsupported features should not have flag/partial_implementation data

[queengooborg]

When working on #6679, I noticed that the linter doesn't prevent features with "version_added": false from having flags, partial_implementation, prefix, or alternative_name. I don't think that it makes sense for an unsupported feature to have anything other than a note. We should add statements to the linter that prevent flags/partial implementation if support is false.

[ddbeck]

Something that would be helpful to move on this: how many features are currently affected by this. If there are few (or no) features with "version_added": false and unexpected fields, then it's pretty easy to change the schema to prevent it. If not, there's a data quality project to work on before we can clamp down the schema.

[ddbeck]

This wasn't resolved by #15551. The PR did remove the data, but didn't change the schema or linting to prevent it from happening in the future.