build: remove @contentstack/cli-launch from bundled CLI (DX-9742)

Demote launch to an opt-in plugin: drop @contentstack/cli-launch from
both the dependencies and the oclif.plugins array in
packages/contentstack/package.json, and regenerate pnpm-lock.yaml to
clear its dependency subtree.

Launch commands are no longer bundled or documented by default; users
install them on demand via `csdx plugins:add @contentstack/cli-launch`
(@oclif/plugin-plugins is already bundled). oclif.manifest.json is
generated at pack time, so it picks up the removal automatically.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: harshitha-cstk

packages/contentstack/package.json

@@ -32,7 +32,6 @@
     "@contentstack/cli-cm-seed": "~2.0.0-beta.24",
     "@contentstack/cli-command": "~2.0.0-beta.10",
     "@contentstack/cli-config": "~2.0.0-beta.14",
-    "@contentstack/cli-launch": "^1.11.1",
     "@contentstack/cli-migration": "~2.0.0-beta.16",
     "@contentstack/cli-utilities": "~2.0.0-beta.11",
     "@contentstack/cli-variants": "~2.0.0-beta.19",
@@ -150,7 +149,6 @@
       "@contentstack/cli-cm-branches",
       "@contentstack/cli-audit",
       "@contentstack/cli-cm-import-setup",
-      "@contentstack/cli-launch",
       "@contentstack/cli-bulk-operations"
     ],
     "hooks": {