Prevent breakage when merging OSS changes to ENT due to missing funcs (#21564)

Add a go:generate helper called stubmaker, which generates appropriate stubs on ent based on oss stubs, but only when needed (i.e. real ent funcs haven't been added yet.)

scripts/ci-helper.sh

@@ -156,6 +156,8 @@ function build() {
   : "${GO_TAGS:=""}"
   : "${REMOVE_SYMBOLS:=""}"
 
+  GOOS= GOARCH= go generate ./...
+
   # Build our ldflags
   msg="--> Building Vault v$version, revision $revision, built $build_date"