test(admin): download latest perun-rpc

Description

test(admin): download latest perun-rpc

• the perun-rpc war is now downloaded from the package registry instead of releases
• package registry should update with every merge to the main branch
• this will allow us to run e2e tests without waiting for BE release

How to test

Run E2E test locally I suppose. The fact that they pass should be good enough, would like to test by merging into perun main that affects e2e tests, but this is excessively difficult IMO. I suggest just merging and seeing what happens.

Author's checklist

• I have followed the contribution guidelines
• This MR has been tested or does not change functionality
• I have added relevant merge request dependencies (if this MR has any)
• I have added the correct labels
• I have assigned reviewers (if any are relevant)
• I have edited the documentation (if the changes require it) or I have noted the need for the change if I do not have access to the documentation
• I have marked all introduced BREAKING CHANGES or necessary DEPLOYMENT NOTES in the commit message(s)

Reviewer's checklist

• This MR has been tested or does not change functionality
• This MR has correct commit message format

Other information

None

Related issues

Closes STR-1225