Ignore plan_limits.web_hook_calls to avoid using it when it's renamed

What does this MR do and why?

This ignores plan_limits.web_hook_calls explicitly to resolve incident gitlab-com/gl-infra/production#8264 (closed).

More details in gitlab-com/gl-infra/production#8264 (comment 1246724753).

How to set up and validate locally

It is a bit trick to validate this, but here is a try - gitlab-com/gl-infra/production#8264 (comment 1246748134)

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.