[network] Remove conntrack_num_connections

This metric shouldn't be receiving data anymore, so we can clean it up
guilt-free.

Fixed: 449154844
Change-Id: I94ec7f26b6d675e88bd4e54e2c4285886a6a6964
Reviewed-on: https://fuchsia-review.googlesource.com/c/cobalt-registry/+/1566497
Reviewed-by: Sarah Hammond <sarahhammond@google.com>
Privacy-Approval: Sarah Hammond <sarahhammond@google.com>
Fuchsia-Auto-Submit: Peter DeLong <pdelong@google.com>
Commit-Queue: Peter DeLong <pdelong@google.com>
diff --git a/fuchsia/networking/metrics.yaml b/fuchsia/networking/metrics.yaml
index df4c263..25e5a53 100644
--- a/fuchsia/networking/metrics.yaml
+++ b/fuchsia/networking/metrics.yaml
@@ -568,41 +568,6 @@
           step_multiplier_float: 2.0
 
 ###############################################################################
-# conntrack_num_connections
-#
-# The current number of connections currently being tracked by conntrack.
-###############################################################################
-# TODO(https://fxbug.dev/449154844): Remove once it's no longer receiving data.
-- id: 40
-  metric_name: conntrack_num_connections
-  metric_type: INTEGER
-  metric_units_other: "connections"
-  metric_semantics: [USAGE_COUNTING, NETWORK_COMMUNICATION]
-  meta_data:
-    max_release_stage: GA
-    expiration_date: "2026/02/01"
-  metric_dimensions:
-    - dimension: ip_version
-      event_codes:
-        4: ipv4
-        6: ipv6
-  reports:
-    - report_name: per_device_histograms_1day
-      id: 1
-      report_type: UNIQUE_DEVICE_HISTOGRAMS
-      system_profile_selection: SELECT_LAST
-      local_aggregation_period: WINDOW_1_DAY
-      local_aggregation_procedure: MAX_PROCEDURE
-      privacy_mechanism: DE_IDENTIFICATION
-      system_profile_field: [BOARD_NAME, PRODUCT_NAME, CHANNEL, SYSTEM_VERSION]
-      int_buckets:
-        exponential:
-          floor: 0
-          num_buckets: 16
-          initial_step: 10
-          step_multiplier_float: 2.0
-
-###############################################################################
 # conntrack_table_limit_hits
 #
 # The number of times since boot that the conntrack connection limit has been
@@ -843,4 +808,4 @@
       system_profile_field: [BOARD_NAME, PRODUCT_NAME, CHANNEL, SYSTEM_VERSION]
 
 # Deleted metric IDs that must not be reused.
-deleted_metric_ids: [1,2,3,4,5,6,7,8,9,10,11,12,13,14,16,17,18,19,20,21,23,24,25,27]
+deleted_metric_ids: [1,2,3,4,5,6,7,8,9,10,11,12,13,14,16,17,18,19,20,21,23,24,25,27,40]