docs: remove grep from pull rate limit prerequisites (#24455)

## Summary

- Removes `grep` from the prerequisite list in the "View pull rate and
limit" section of `content/manuals/docker-hub/usage/pulls.md`
- The three commands shown in that section only use `curl` and `jq` —
`grep` is never referenced
- Fixes a factual error that would cause unnecessary confusion for
readers checking whether they have the required tools

Closes #24436

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Co-authored-by: Docker Docs Agent <agent@docker-docs-harness.local>

content/manuals/docker-hub/usage/pulls.md

@@ -168,7 +168,7 @@ To view your current pull rate and limit:
 
 > [!NOTE]
 >
-> To check your limits, you need `curl`, `grep`, and `jq` installed.
+> To check your limits, you need `curl` and `jq` installed.
 
 1. Get a token.
    - To get a token anonymously, if you are pulling anonymously: