mgr/dashboard: fix rgw multi-site import form helper

mgr/dashboard: fix rgw multi-site import form helper

Before : To obtain the token, generate it from your primary Ceph cluster. This token includes encoded information about the secondary cluster's endpoint, access key, and secret key.
Fix: To obtain the token, generate it from your primary Ceph cluster. This token includes encoded information about the primary cluster's endpoint, access key, and secret key.

Fixes: https://tracker.ceph.com/issues/63469
Signed-off-by: Aashish Sharma <aasharma@redhat.com>