Imgpkg describe fails to print the output for the larger images

**What steps did you take:**
```
$imgpkg describe -b somebundle.oci.image:tag --json
$
```

**What happened:**
Imgpkg describe took more than 5 minutes and failed to print anything.
When the bundle size is small it prints the output. But, for a specific bundle which has 118 image references took more than five minutes and printed nil output in the UI.

**What did you expect:**
Performance of imgpkg has to be improved to print the description for larger images.

**Anything else you would like to add:**
[Additional information that will assist in solving the issue.]

**Environment:**

- imgpkg version (use `imgpkg --version`): **v0.41.1**
- Docker registry used (e.g. `Docker HUB`):
- OS (e.g. from `/etc/os-release`):

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