Description of problem:
create or Edit of user with username containing '.', eg: test.user fails with error " The value is not valid. "

Version-Release number of selected component (if applicable):
ceph version 18.2.0-122.el9cp

How reproducible:
Always

Steps to Reproduce:
1. ceph cluster deployed on 7.0
2. Create or  Edit of user with username containing '.' eg: test.user fails with 'The value is not valid.' 
3. Please note: the user creation and edit succeeds from CLI

snippet: 
1. user create 
[root@ceph-rgw-7-e863q4-node1-installer ~]# radosgw-admin user create --uid testuser --display-name test.user
{
    "user_id": "testuser",
    "display_name": "test.user",
    "email": "",
    "suspended": 0,
    "max_buckets": 1000,
    "subusers": [],
    "keys": [
        {
            "user": "testuser",
            "access_key": "NCTDCMYS7Q9M34JD4Y3V",
            "secret_key": "mlgVfiTwNsf3Ta0s5y3HFsE6FJcKM5BqXxAvVvuC"
        }
    ],
    "swift_keys": [],
    "caps": [],
    "op_mask": "read, write, delete",
    "default_placement": "",
    "default_storage_class": "",
    "placement_tags": [],
    "bucket_quota": {
        "enabled": false,
        "check_on_raw": false,
        "max_size": -1,
        "max_size_kb": 0,
        "max_objects": -1
    },
    "user_quota": {
        "enabled": false,
        "check_on_raw": false,
        "max_size": -1,
        "max_size_kb": 0,
        "max_objects": -1
    },
    "temp_url_keys": [],
    "type": "rgw",
    "mfa_ids": []
}

2. user edit -> suspend
[root@ceph-rgw-7-e863q4-node1-installer ~]# radosgw-admin user suspend --uid testuser
{
    "user_id": "testuser",
    "display_name": "test.user",
    "email": "",
    "suspended": 1,
    "max_buckets": 1000,
    "subusers": [],
    "keys": [
        {
            "user": "testuser",
            "access_key": "NCTDCMYS7Q9M34JD4Y3V",
            "secret_key": "mlgVfiTwNsf3Ta0s5y3HFsE6FJcKM5BqXxAvVvuC"
        }
    ],
    "swift_keys": [],
    "caps": [],
    "op_mask": "read, write, delete",
    "default_placement": "",
    "default_storage_class": "",
    "placement_tags": [],
    "bucket_quota": {
        "enabled": false,
        "check_on_raw": false,
        "max_size": -1,
        "max_size_kb": 0,
        "max_objects": -1
    },
    "user_quota": {
        "enabled": false,
        "check_on_raw": false,
        "max_size": -1,
        "max_size_kb": 0,
        "max_objects": -1
    },
    "temp_url_keys": [],
    "type": "rgw",
    "mfa_ids": []
}
Actual results:
Create or edit of user fails

Expected results:
Create or edit of user succeeds

Additional info:

PFA, the screen shot of error