ci(release): stop creating deployments for release tags (#39966)

Each `release-create-tag` run created a deployment record, which makes
GitHub show a useless "This branch has not been deployed" box on every
PR:

<img width="819" height="113" alt="image"
src="https://github.com/user-attachments/assets/129c8348-1d70-46b9-8996-8872c84a11f2"
/>

With `deployment: false`, the `release-signing` approval and branch
policy still apply.

.github/workflows/release-create-tag.yml

@@ -13,7 +13,9 @@ permissions: {}
 jobs:
   tag:
     runs-on: ubuntu-latest
-    environment: release-signing
+    environment:
+      name: release-signing
+      deployment: false
     steps:
       - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
         with: