Update alert settings GraphQL create mutation naming

What does this MR do?

A small MVC to address: !55016 (comment 516353036)

thought: Those mutations' names are somewhat inconsistent. For example this one is called createHttpIntegration in the client-side but refers to the httpIntegrationCreate mutation in the GraphQL schema. It might be nice to align those names 🤷

We just use this merge to align the create mutation file/call names with their schema counterpart 😄

Screenshots (strongly suggested)

N/A

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• [-] Code review guidelines
• [-] Merge request performance guidelines
• [-] Style guides
• [-] Database guides
• [-] Separation of EE specific content

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

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] 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
• [-] Security reports checked/validated by a reviewer from the AppSec team