chore(oauth2): enable user impersonation by default

[betodealmeida]

SUMMARY

When configuring a database, if the user provides OAuth2 client information (ID and secret) then we should automatically enable user impersonation for them.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

WIP

TESTING INSTRUCTIONS

ADDITIONAL INFORMATION

• [ ] Has associated issue:
• [ ] Required feature flags:
• [ ] Changes UI
• [ ] Includes DB Migration (follow approval process in SIP-59)
  • [ ] Migration is atomic, supports rollback & is backwards-compatible
  • [ ] Confirm DB migration upgrade and downgrade tested
  • [ ] Runtime estimates and downtime expectations provided
• [ ] Introduces new feature or API
• [ ] Removes existing feature or API

[villebro]

Is user impersonation really needed for OAuth? I would have assumed OAuth mostly makes user impersonation redundant, as you already have full user-specific authentication in place (no need for a service account).