fix(authentication): reconcile logged in users metric

[it2022031]

What kind of change does this PR introduce?

• Bugfix
• Feature
• Code style update
• Refactor
• Build-related changes
• Other (please describe)

Does this PR introduce a breaking change?

• Yes
• No

The PR fulfills these requirements:

• It's submitted to the main branch
• When resolving a specific issue, it's referenced in the PR's description (e.g. fix #xxx, where "xxx" is the issue number)

If adding a new feature, the PR's description includes:

• A convincing reason for adding this feature

Other information:

This PR improves the accuracy of the logged_in_users_total authentication metric.

Previously, the metric could become inconsistent because expired sessions were not always removed correctly when tokens expired naturally over time. As a result, logged_in_users_total could temporarily report incorrect values.

Additionally, the metric was effectively tracking active tokens instead of unique logged-in users, meaning the same user could be counted multiple times across different sessions.

This PR centralizes logged-in user metric updates in TokenProvider and improves cleanup/reconciliation logic so the metric reflects unique active logged-in users more reliably across authentication flows, token refreshes, session invalidation, and expired token cleanup.

No breaking changes are introduced.

[kkopanidis]

Unnecessary duplication present. The "provideUserTokens" function can be utilized to call the "addLoggedInUser" and "reconcileLoggedInUserMetric", instead of adding it everywhere in the code