Remove default push rule override for MSC1930 (#2376)

Folks have had since Matrix 1.0 (June 2019) to upgrade to a compatible server

src/pushprocessor.ts

@@ -56,31 +56,6 @@ const RULEKINDS_IN_ORDER = [
 //   2. We often want to start using push rules ahead of the server supporting them,
 //      and so we can put them here.
 const DEFAULT_OVERRIDE_RULES: IPushRule[] = [
-    {
-        // For homeservers which don't support MSC1930 yet
-        rule_id: ".m.rule.tombstone",
-        default: true,
-        enabled: true,
-        conditions: [
-            {
-                kind: ConditionKind.EventMatch,
-                key: "type",
-                pattern: "m.room.tombstone",
-            },
-            {
-                kind: ConditionKind.EventMatch,
-                key: "state_key",
-                pattern: "",
-            },
-        ],
-        actions: [
-            PushRuleActionName.Notify,
-            {
-                set_tweak: TweakName.Highlight,
-                value: true,
-            },
-        ],
-    },
     {
         // For homeservers which don't support MSC2153 yet
         rule_id: ".m.rule.reaction",