refactor: unify onboarding dm/group policy scaffolding

extensions/nextcloud-talk/src/onboarding.ts

@@ -1,5 +1,4 @@
 import {
-  addWildcardAllowFrom,
   formatDocsLink,
   hasConfiguredSecretInput,
   mergeAllowFromEntries,
@@ -7,6 +6,7 @@ import {
   resolveAccountIdForConfigure,
   DEFAULT_ACCOUNT_ID,
   normalizeAccountId,
+  setTopLevelChannelDmPolicyWithAllowFrom,
   type SecretInput,
   type ChannelOnboardingAdapter,
   type ChannelOnboardingDmPolicy,
@@ -23,24 +23,13 @@ import type { CoreConfig, DmPolicy } from "./types.js";
 const channel = "nextcloud-talk" as const;
 
 function setNextcloudTalkDmPolicy(cfg: CoreConfig, dmPolicy: DmPolicy): CoreConfig {
-  const existingConfig = cfg.channels?.["nextcloud-talk"];
-  const existingAllowFrom: string[] = (existingConfig?.allowFrom ?? []).map((x) => String(x));
-  const allowFrom: string[] =
-    dmPolicy === "open" ? (addWildcardAllowFrom(existingAllowFrom) as string[]) : existingAllowFrom;
-
-  const newNextcloudTalkConfig = {
-    ...existingConfig,
+  return setTopLevelChannelDmPolicyWithAllowFrom({
+    cfg,
+    channel: "nextcloud-talk",
     dmPolicy,
-    allowFrom,
-  };
-
-  return {
-    ...cfg,
-    channels: {
-      ...cfg.channels,
-      "nextcloud-talk": newNextcloudTalkConfig,
-    },
-  } as CoreConfig;
+    getAllowFrom: (inputCfg) =>
+      (inputCfg.channels?.["nextcloud-talk"]?.allowFrom ?? []).map((entry) => String(entry)),
+  }) as CoreConfig;
 }
 
 function setNextcloudTalkAccountConfig(