Added support to assume another target IAM role for aws IAM auth method in case of Jenkins controller is running on different aws account and vault is on different.
Testing done
I have tested with Controller running with one aws account and vault is configured with different aws account.
### Submitter checklist
- [ ] Make sure you are opening from a **topic/feature/bugfix branch** (right side) and not your main branch!
- [ ] Ensure that the pull request title represents the desired changelog entry
- [ ] Please describe what you did
- [ ] Link to relevant issues in GitHub or Jira
- [ ] Link to relevant pull requests, esp. upstream and downstream changes
- [ ] Ensure you have provided tests - that demonstrates feature works or fixes the issue
Added support to assume another target IAM role for aws IAM auth method in case of Jenkins controller is running on different aws account and vault is on different.
Testing done
I have tested with Controller running with one aws account and vault is configured with different aws account.