nxos_bgp: Fix idempotence for event-history (#27329)

* Fix idempotence for event-history

* `event-history detail` defaults to `False`, the rest to `size_small`

lib/ansible/modules/network/nxos/nxos_bgp.py

@@ -360,9 +360,9 @@ PARAM_TO_DEFAULT_KEYMAP = {
     'suppress_fib_pending': True,
     'fast_external_fallover': True,
     'enforce_first_as': True,
-    'event_history_periodic': True,
     'event_history_cli': True,
-    'event_history_events': True
+    'event_history_events': True,
+    'event_history_periodic': True,
 }
 PARAM_TO_COMMAND_KEYMAP = {
     'asn': 'router bgp',
@@ -412,14 +412,16 @@ def get_value(arg, config):
 
     if command.split()[0] == 'event-history':
         command_re = re.compile(r'\s+{0}\s*'.format(command), re.M)
+        has_size = re.search(r'^\s+{0} size\s(?P<value>.*)$'.format(command), config, re.M)
 
-        size_re = re.compile(r'(?:{0} size\s)(?P<value>.*)'.format(command), re.M)
+        if command == 'event-history detail':
             value = False
+        else:
+            value = 'size_small'
 
         if command_re.search(config):
-            search = size_re.search(config)
-            if search:
-                value = search.group('value')
+            if has_size:
+                value = 'size_%s' % has_size.group('value')
             else:
                 value = True
 
@@ -431,10 +433,10 @@ def get_value(arg, config):
             value = False
 
     elif arg in BOOL_PARAMS:
-        command_re = re.compile(r'\s+{0}\s*'.format(command), re.M)
+        has_command = re.search(r'^\s+{0}\s*$'.format(command), config, re.M)
         value = False
 
-        if command_re.search(config):
+        if has_command:
             value = True
     else:
         command_val_re = re.compile(r'(?:{0}\s)(?P<value>.*)'.format(command), re.M)