[BUG] JsonToStructs and ScanJson do not fall back/support it properly if single quotes are disabled

[revans2]

Describe the bug
Up until recently single quote support was not in JsonToStructs or ScanJson. It was recently enabled, but when the config is enabled it does not fall back to the CPU or disable the feature and do the right thing.

[revans2]

I am putting up a PR to fall back correctly when needed, but I tried to actually enable not supporting single quoted strings, but that would result in CUDF returning the full value as if it were a string.

{"str": 'World'}

resulted in 'World' being returned. This is even with mixed types as strings disabled.