chore(auth): drop the unused MICROSOFT_TENANT_ID knob

Hosted Sim serves many Entra tenants, so it must stay on the multi-tenant
endpoint — pinning is only meaningful for a self-hoster restricting sign-in to
their own directory, and nobody is asking for that yet. The xms_edov fix is
independent of the tenant setting, so this removes surface without touching
behavior.

Author: waleedlatif1

apps/sim/lib/auth/auth.ts

@@ -760,7 +760,6 @@ export const auth = betterAuth({
             clientId: env.MICROSOFT_CLIENT_ID,
             clientSecret: env.MICROSOFT_CLIENT_SECRET,
             scope: ['openid', 'profile', 'email'],
-            ...(env.MICROSOFT_TENANT_ID ? { tenantId: env.MICROSOFT_TENANT_ID } : {}),
             /**
              * Without this, `/common/` silently reuses whichever Microsoft
              * session the browser already holds, so someone signed into a

apps/sim/lib/core/config/env.ts

@@ -440,7 +440,6 @@ export const env = createEnv({
     DOCUSIGN_CLIENT_SECRET:                z.string().optional(),                  // DocuSign OAuth client secret
     MICROSOFT_CLIENT_ID:                   z.string().optional(),                  // Microsoft OAuth client ID for Office 365/Teams
     MICROSOFT_CLIENT_SECRET:               z.string().optional(),                  // Microsoft OAuth client secret
-    MICROSOFT_TENANT_ID:                   z.string().optional(),                  // Microsoft sign-in tenant: a GUID, 'organizations' (work/school only), or 'common' (default)
     HUBSPOT_CLIENT_ID:                     z.string().optional(),                  // HubSpot OAuth client ID
     HUBSPOT_CLIENT_SECRET:                 z.string().optional(),                  // HubSpot OAuth client secret
     SALESFORCE_CLIENT_ID:                  z.string().optional(),                  // Salesforce OAuth client ID