[code-infra] Allow dispatch of manual cherry-pick workflow (#16299)

.github/workflows/create-cherry-pick-pr.yml

@@ -3,6 +3,16 @@ on:
   pull_request_target:
     branches: [master, next, 'v[0-9]+.x']
     types: [closed]
+  workflow_dispatch:
+    inputs:
+      target_branch:
+        description: 'A target branch passed from the caller workflow'
+        required: true
+        type: string
+      pr_number:
+        description: 'The PR number to cherry-pick from'
+        required: true
+        type: string
 
 permissions: {}
 
@@ -13,3 +23,6 @@ jobs:
     permissions:
       contents: write
       pull-requests: write
+    with:
+      target_branch: ${{ inputs.target_branch }}
+      pr_number: ${{ inputs.pr_number }}