[Enhancement] Add Multi-Auth integration test into e2e functional testing by using Cypress 13

[RyanL1997]

Is your feature request related to a problem?
In #1655, it introduced two new e2e workflows for testing external auths of OIDC and SAML for Security frontend. And the security frontend also contains the test of saml_multiauth (see here). We should transfer this into another e2e workflow and also add the coverage for OIDC when multi-auth is configured.

Pre-requisite

• The merge of Cypress13 testing frame work for OIDC and SAML #1579

Exit Criteria

• Refactor the saml_multiauth test into a e2e cypress workflow
• Add the coverage for OIDC when multi-auth is enabled

[cwperks]

[Triage] Thank you for filing this issue @RyanL1997 . This is now unblocked since Cypress 13 tests were added to this repo last week.

[cwperks]

Closing since #1729 has been merged.