feat: enforce concurrent session limit with login picker (CW-7169) (#14621)

## Description

Cap active sessions at `MAX_USER_SESSIONS` which defaults to existing
value of `25` per user. This ensure existing user login behavior is not
affected for self-hosted installations. Browser users at the cap see a
session picker (409 response) to choose which session to end.
Non-browser clients and partially-tracked users get silent
oldest-session eviction.

Depends on #14556.

## Type of change

- [x] New feature (non-breaking change which adds functionality)

## How Has This Been Tested?

Specs cover: under limit, at limit (browser picker, non-browser
eviction), partial tracking fallback, revoke single/all sessions during
login, session row creation on successful login.

---------

Co-authored-by: Sony Mathew <sony@chatwoot.com>

app/javascript/v3/api/auth.js

@@ -43,6 +43,15 @@ export const login = async ({
         mfaToken: error.response.data.mfa_token,
       };
     }
+    if (
+      error.response?.status === 409 &&
+      error.response?.data?.sessions_limit_reached
+    ) {
+      return {
+        sessionsLimitReached: true,
+        sessions: error.response.data.sessions,
+      };
+    }
     const loginError = new Error(parseAPIErrorResponse(error));
     loginError.errorCode = error.response?.data?.error_code;
     throw loginError;