[Scripts] upgrade to using DPM

[PHOL-DA]

we should upgrade the repo to use DPM instead of daml assistance:

WARNING: Daml Assistant has been deprecated and replaced with the Digital Asset Package Manager (DPM)
See intallation here: https://docs.digitalasset.com/build/3.4/dpm/dpm.html
Daml Assistant will be removed in 3.5
You can disable this warning with --no-legacy-assistant-warning

(this can be see in running script:fetch:daml-sdk)