Rename mem_pool_index tag to mem in cisco-firepower-asa profile (DataDog#24582)

Aligns with other profiles (e.g. cisco-nexus) that tag CISCO-ENHANCED-MEMPOOL-MIB memory metrics with mem instead of mem_pool_index.

Author: TCheruy

snmp/datadog_checks/snmp/data/default_profiles/cisco-firepower-asa.yaml

@@ -52,7 +52,7 @@ metrics:
         symbol:
           OID: 1.3.6.1.4.1.9.9.221.1.1.1.1.3
           name: cempMemPoolName
-      - tag: mem_pool_index
+      - tag: mem
         index: 1
   - MIB: CISCO-REMOTE-ACCESS-MONITOR-MIB
     symbol:

snmp/tests/test_e2e_core_profiles/test_profile_cisco_firepower_asa.py

@@ -49,7 +49,7 @@ def test_e2e_profile_cisco_firepower_asa(dd_agent_check):
     aggregator.assert_metric('snmp.crasNumSetupFailInsufResources', metric_type=aggregator.COUNT, tags=common_tags)
     aggregator.assert_metric('snmp.crasNumUsers', metric_type=aggregator.GAUGE, tags=common_tags)
     mem_tag_rows = [
-        ['mem_pool_index:1', 'mem_pool_name:System memory'],
+        ['mem:1', 'mem_pool_name:System memory'],
     ]
     for tag_row in mem_tag_rows:
         aggregator.assert_metric('snmp.memory.free', metric_type=aggregator.GAUGE, tags=common_tags + tag_row)