Extend Econ Gov testing coverage

[Jorge-Lopes]

Extend z:acceptance testing coverage of Econ Gov according to the functionalities identified on this document

Note: Some functionalities are already covered by existing test cases that are present in other test files. We intend to migrate them to this dedicated test file.

Tasks

Beta Give feedback

1. For new EC members, EC member can accept invitation to charter and successfully propose and vote
2. EC member can propose PSM or Vault contract or parameter change
3. EC member can view active change proposals
4. EC member can vote on active change proposal
5. EC member can see historical proposals
6. Proposal succeeds and is applied after quorum met and vote is successful
7. Configured EC parameters are intact following change or upgrade