Match ZeitConsens user case-insensitively

The saved tapi-zc-user and the server's MA_USER_NAME are compared
to decide whether to auto-switch the 3CX presence. A mismatch in
capitalization between the two sources silently disabled the sync,
so both are lowercased before comparison.

client/src/status.ts

@@ -42,7 +42,7 @@ export class Status {
     if (!this._enabled || !this._user) {
       return;
     }
-    var entry = avs.find(a => a.user === this._user);
+    var entry = avs.find(a => a.user.toLowerCase() === this._user.toLowerCase());
     if (!entry) {
       return;
     }