chore: revert 1P pipeline ref to dev; fix changefile comment

- Revert .pipelines/1p-e2e.yml 1P resource ref back to dev (temp
  dependency-updates ref was only needed during active branch work)
- Fix changefile comment to use conventional commit prefix and match
  the actual package-level change (@rollup/plugin-terser upgrade)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: hectormmg

.pipelines/1p-e2e.yml

@@ -34,7 +34,7 @@ resources:
         - repository: 1P
           type: git
           name: IDDP/msal-javascript-1p
-          ref: dependency-updates
+          ref: dev
 
 extends:
     template: v2/OneBranch.NonOfficial.CrossPlat.yml@templates # https://aka.ms/obpipelines/templates

change/@azure-msal-browser-dep-cve-fixes.json

@@ -1,6 +1,6 @@
 {
   "type": "patch",
-  "comment": "Upgrade @rollup/plugin-terser to v1 to fix serialize-javascript CVE",
+  "comment": "fix: upgrade @rollup/plugin-terser to v1 to address serialize-javascript CVE",
   "packageName": "@azure/msal-browser",
   "email": "hemoral@microsoft.com",
   "dependentChangeType": "patch"