Fix scripts for local testnet in multikey mode

[sstanculeanu]

Reasoning behind the pull request

• with the deprecation of -no-key flag, the local testnets scripts would start the observers as multi key nodes

Proposed changes

• fix scripts

Testing procedure

• only scripts changes

Pre-requisites

Based on the Contributing Guidelines the PR author and the reviewers must check the following requirements are met:

• was the PR targeted to the correct branch?
• if this is a larger feature that probably needs more than one PR, is there a feat branch created?
• if this is a feat branch merging, do all satellite projects have a proper tag inside go.mod?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (d5bb384) 80.18% compared to head (9de76e0) 80.15%.

Additional details and impacted files

@@                Coverage Diff                @@
##           rc/v1.6.next1    #5940      +/-   ##
=================================================
- Coverage          80.18%   80.15%   -0.03%     
=================================================
  Files                709      709              
  Lines              94135    94135              
=================================================
- Hits               75486    75458      -28     
- Misses             13301    13330      +29     
+ Partials            5348     5347       -1     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.