Make some alerts warnings instead of critical (#8739)

substrate/.maintain/monitoring/alerting-rules/alerting-rule-tests.yaml

@@ -175,7 +175,7 @@ tests:
                       polkadot-abcdef01234-abcdef has been monotonically
                       increasing for more than 10 minutes."
                 - exp_labels:
-                      severity: critical
+                      severity: warning
                       pod: polkadot-abcdef01234-abcdef
                       instance: polkadot-abcdef01234-abcdef
                       job: polkadot
@@ -190,7 +190,7 @@ tests:
             # same. Thus expect an alert.
             exp_alerts:
                 - exp_labels:
-                      severity: critical
+                      severity: warning
                       pod: polkadot-abcdef01234-abcdef
                       instance: polkadot-abcdef01234-abcdef
                       job: polkadot

substrate/.maintain/monitoring/alerting-rules/alerting-rules.yaml

@@ -74,7 +74,7 @@ groups:
     increase(polkadot_sub_txpool_validations_finished[5m]) > 0'
     for: 30m
     labels:
-      severity: critical
+      severity: warning
     annotations:
       message: 'The transaction pool size on node {{ $labels.instance }} has
       been monotonically increasing for more than 30 minutes.'
@@ -83,7 +83,7 @@ groups:
     polkadot_sub_txpool_validations_finished > 10000'
     for: 5m
     labels:
-      severity: critical
+      severity: warning
     annotations:
       message: 'The transaction pool size on node {{ $labels.instance }} has
       been above 10_000 for more than 5 minutes.'