module grafana_dashboard fix for work python3 (#47708)

* fix for work python3

change string to str for work in python3

* delete unusin import module

lib/ansible/modules/monitoring/grafana_dashboard.py

@@ -136,7 +136,6 @@ uid:
 '''
 
 import json
-import string
 
 from ansible.module_utils.basic import AnsibleModule
 from ansible.module_utils.urls import fetch_url, url_argument_spec
@@ -184,7 +183,7 @@ def get_grafana_version(module, grafana_url, headers):
     if info['status'] == 200:
         try:
             settings = json.loads(r.read())
-            grafana_version = string.split(settings['buildInfo']['version'], '.')[0]
+            grafana_version = str.split(settings['buildInfo']['version'], '.')[0]
         except Exception as e:
             raise GrafanaAPIException(e)
     else: