Your upgrade is failing as it is not able to establish connection to Data Warehouse schema (PPM_DWH). Is it mandatory to create a Data Warehouse database for the upgrade if you are not using it.
Environment
Release : 15.4+
Component : CA PPM DATA WAREHOUSE
Resolution
Starting Clarity version 15.4 Data Warehouse is required.
Here is the documentation that states it as well: Clarity Documentation Section: Pre-Upgrade: Installation and Upgrade Dependencies
If you are not using DWH you can just create a schema and use it for the Clarity upgrade, and PMO upgrade.
Keep in mind that all OOTB reports will be based off Data Warehouse so you might want to look into it to be able to use them.