Whether tax evaded under State GST Act or IGST Act would also be taken in to account for the purpose of the prosecution

Yes. In terms of explanation to Section 132 the term tax has been defined to include amount of tax evaded or the amount of input tax credit wrongly availed or utilised or refund wrongly taken under the provisions of this Act, the State Goods and Services Tax Act, the Integrated Goods and Services Tax Act or the Union Territory Goods and Services Tax Act and cess levied under the Goods and Services Tax (Compensation to States) Act.

(ICAI FAQ PUBLICATIONS 06-09-2017 Punishment for Certain Offences: FAQ NO. 29)