Fix error message to reflect command. (backport #13451)

[mergify]

Proposed Changes

Fixes an error message that incorrectly said add when the command was delete.

Types of Changes

What types of changes does your code introduce to this project?
Put an x in the boxes that apply

• Bug fix
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause an observable behavior change in existing systems)
• Documentation improvements (corrections, new content, etc)
• Cosmetic change (whitespace, formatting, etc)
• Build system and/or CI

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This is an automatic backport of pull request #13451 done by [Mergify](https://mergify.com).