Make local and pack the files having linked groups

I have a rig file having a character rig with group named as “character_grp”. I linked the character_grp in my animation work file.
Then made proxy and animated the character.

Now I want to strip of any external dependencies and pack the animation work file to send it to client/renderFarm.
Can’t make the linked group local with Object > Make Local.
File > External Data > Pack all in to .blend file doesn’t pack the linked group.

How can I pack the files which I already created in this approach?
What is the pipeline you guys follow in this scenario?

Ps. I found a old bug report regarding the same issue