Do not mask key comments for DeployKeys

What does this MR do?

Fixes #223218 (closed)

• As part of !34255 (merged), we also masked key comments for Deploy Keys, which inadvertently broke the terraform provider: https://github.com/terraform-providers/terraform-provider-gitlab/issues/338.

• Also, as deploy keys are always exposed behind authenticated API endpoints, there is practically no risk of leaking sensitive info from the key comments of Deploy Keys to bad actors.

Combining these 2 reasons, we can safely expose comments of Deploy Keys without masking them.

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
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Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

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• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
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