Shell completion not working for KV v2 mounts

[georgethebeatle]

Describe the bug
Shell completion list/put/patch for KV v2 paths is always empty

To Reproduce
Steps to reproduce the behavior:

1. Create a vault instance with the following structure:

- kvv1 (mount of type kv, version 1)
  - a
    - b
- kvv2 (mount of type kv, version 2)
  - c
    - d

2. Run vault kv delete kvv1/<tab>, I get kvv1/a/b as a suggestion.
3. Run vault kv delete kvv2/<tab>, the suggestion list is empty.

Expected behavior
I would expect that the kvv2 suggestions are not empty and contain kvv2/c/d, similarly to what I get for kvv1

Environment:

• Vault Server Version (retrieve with vault status): 1.10.3
• Vault CLI Version (retrieve with vault version): 1.12.0
• Server Operating System/Architecture: Linux vault-0 5.10.109+ #1 SMP Tue May 24 09:08:48 UTC 2022 x86_64 Linux (running on kubernetes pod)

[HridoyRoy]

Hi @georgethebeatle , thanks for opening the PR! I've left a few comments on it, but the functional code changes look good!