Add support for having keyword for Service Ping metric name suggestion

What does this MR do and why?

Related to #332467 (closed)

We want to support having SQL keyword when generating name suggestions for Service Ping metrics.

Screenshots or screen recordings

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How to set up and validate locally

To test the MR, we can use the example from the linked issue, to make sure that these two metrics produce different suggestions now, by running this in the console:

name1 = Gitlab::Usage::Metrics::NamesSuggestions::Generator.generate('usage_activity_by_stage_monthly.create.approval_project_rules_with_more_approvers_than_required')
name2 = Gitlab::Usage::Metrics::NamesSuggestions::Generator.generate('usage_activity_by_stage_monthly.create.approval_project_rules_with_less_approvers_than_required')

Now, the variables should have different values:

name1 == name2
=> false

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.