Add high availability support to Nutanix (#24161)

* feat(nutanix): add high availability support

Declare HA_SUPPORTED so the Agent can run the Nutanix check in an HA
group with a single active runner and failover, avoiding duplicate
collection from the central Prism Central API.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

* docs(nutanix): add changelog entry for HA support

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: NouemanKHAL

nutanix/changelog.d/24161.added

@@ -0,0 +1 @@
+Add high availability (HA) support.

nutanix/datadog_checks/nutanix/check.py

@@ -17,6 +17,7 @@
 
 class NutanixCheck(AgentCheck, ConfigMixin):
     __NAMESPACE__ = 'nutanix'
+    HA_SUPPORTED = True
     HTTP_CONFIG_REMAPPER = {'pc_username': {'name': 'username'}, 'pc_password': {'name': 'password'}}
 
     def __init__(self, name, init_config, instances):