Docs: fix API move issue curl command

What does this MR do?

This is a minor update to fix the Move issue CURL command on the API Issues page. The existing one will throw an error.

Related issues

For further discussion and context, slack discussion (internal)

Author's checklist

• Apply the correct labels and milestone

All others are N/A

• Crosslink the document from the higher-level index
• Crosslink the document from other subject-related docs
• Feature moving tiers? Make sure the change is also reflected in features.yml
• Correctly apply the product badges and tiers
• Port the MR to EE (or backport from CE): always recommended, required when the ee-compat-check job fails

Review checklist

• Your team's review (required)
• PM's review (recommended, but not a blocker)
• Technical writer's review (required)
• Merge the EE-MR first, CE-MR afterwards

@gl-docsteam for quick review and merge