fix: publish 2.x on the latest channel; drop broken release assets

Normalize the release config to main's plugins-array form and publish
the 2.x line to the `latest` dist-tag.

Putting a maintenance branch on `latest` is safe only because the 2.x
line publishes a different npm package (@edx/frontend-plugin-notifications)
than release/main (@openedx/frontend-app-notifications), so their `latest`
tags are independent. If they shared a package, the maintenance and
release lines would clobber each other's `latest`, and 2.x would have to
keep its own channel instead.

Also drop the dist/* GitHub release asset upload, which fails under the
current @semantic-release/github stack, and keep success/fail disabled to
preserve existing behavior.

Co-Authored-By: Claude <noreply@anthropic.com>

Author: arbrandes

.releaserc

@@ -1,30 +1,15 @@
 {
   "branches": [
-    { "name": "release", "channel": "latest" },
+    "release",
     { "name": "main", "prerelease": "alpha", "channel": "alpha" },
-    "2.x"
+    { "name": "2.x", "channel": "latest" }
   ],
   "tagFormat": "v${version}",
-  "verifyConditions": [
+  "plugins": [
+    "@semantic-release/commit-analyzer",
+    "@semantic-release/release-notes-generator",
     "@semantic-release/npm",
-    {
-      "path": "@semantic-release/github",
-      "assets": {
-        "path": "dist/*"
-      }
-    }
-  ],
-  "analyzeCommits": "@semantic-release/commit-analyzer",
-  "generateNotes": "@semantic-release/release-notes-generator",
-  "prepare": "@semantic-release/npm",
-  "publish": [
-    "@semantic-release/npm",
-    {
-      "path": "@semantic-release/github",
-      "assets": {
-        "path": "dist/*"
-      }
-    }
+    "@semantic-release/github"
   ],
   "success": [],
   "fail": []