Fix copy paste error in new workflows (microsoft#57611)

Author: jakebailey

.github/workflows/new-release-branch.yaml

@@ -6,7 +6,7 @@ on:
       branch_name:
         description: Release branch name to create
         required: true
-        type: number
+        type: string
       package_version:
         description: Release package version
         required: true

.github/workflows/set-version.yaml

@@ -6,7 +6,7 @@ on:
       branch_name:
         description: Release branch name to create
         required: true
-        type: number
+        type: string
       package_version:
         description: Release package version
         required: true

.github/workflows/sync-branch.yaml

@@ -6,7 +6,7 @@ on:
       branch_name:
         description: Release branch name to create
         required: true
-        type: number
+        type: string
 
       # Inputs provided by the bot
       distinct_id: