fix from_type_str for TypeTag

[Yolley]

• strip value in _reducer as it can have an extra space after splitting by ,;
• pass lowest_level as is if it's a list, otherwise it leads to an issue for types that have their own type tag;

Here is an example type that will be parsed correctly, without this fix it will fail

0xb24b6789e088b876afabca733bed2299fbc9e2d6369be4d1acfa17d8145454d9::swap::LSP<0x2::sui::SUI, 0x239e9725bdab1fcb2e4798a057da809e52f13134a09bc9913659d4a80ddfdaad::shui::SHUI>