RetrieveTeam and ListTeamMembers APIs are slow for orgs with many teams/members

[dalnoki]

Environment

SaaS (https://sentry.io/)

Steps to Reproduce

Summary

RetrieveTeam and ListTeamMembers endpoints have high mean response times and occasional
spikes up to 1 minute. Reported by a customer using both endpoints directly via API as part
of an automated GitHub → Sentry sync process. Please find additional details in the Linear ticket.

Affected Endpoints

Endpoint	Params	Mean Response Time
GET /api/0/teams/{org}/{team}/	expand=externalTeams	14.4s
GET /api/0/teams/{org}/{team}/members/	per_page=50, cursor pagination	16.2s

Reproduction

1. Call GET /api/0/teams/{org}/{team}/?expand=externalTeams on an org with many external
   team mappings
2. Call GET /api/0/teams/{org}/{team}/members/?per_page=50 with cursor pagination on an
   org with many team members
3. Does not reproduce on small test orgs

Expected Result

Both endpoints should respond faster regradless of org size

Actual Result

Both endpoints return correct results but take 14-16s mean response time on orgs with many team mappings.

Product Area

Settings - Integrations

Link

No response

DSN

No response

Version

No response

[getsantry]

Assigning to @getsentry/support for routing ⏲️

[linear-code]

ENG-7939

[getsantry]

Routing to @getsentry/product-owners-settings-integrations for triage ⏲️