Keycloak multitenant service

[madicnikola]

Issue Description

In multi-tenant mode, the logic for resolving instances in the keycloak-multitenant.service.ts has a flaw. When resolveAlways is enabled, the existing instance is not correctly updated with the new configuration (authServerUrl, secret).
More precisely the keycloak.grantManager resulting in errors: Cannot validate access token: Error: Grant validation failed. Reason: invalid token (wrong ISS) even when resolveAlways config is set to true

Steps to Reproduce

1. Enable multi-tenant mode.
2. Set resolveAlways to true.
3. Observe that the instance is not updated properly with the latest configuration.

Expected Behavior

When resolveAlways is enabled, the existing instance should be updated with the new authServerUrl and secret.

Actual Behavior

The existing instance is not updated correctly, leading to outdated configurations.