[Vue] add utility function for pattern that issues a single AJAX request at a time #19239

Description:

This PR adds a new method that issues an AJAX request after aborting the existing ongoing request if one exists. This is a pattern I've seen a lot, it seemed worth adding a utility function to core.

Usage:

defineComponent({
  methods: {
    performRequest: oneAtATime<ResponseType>('MyPlugin.myMethod'),
    doSomething() {
      this.performRequest({ idSite, period, ... }).then(() => {
        // ...
      });
    },
  },
});

Review

• [ ] Functional review done
• [ ] Potential edge cases thought about (behavior of the code with strange input, with strange internal state or possible interactions with other Matomo subsystems)
• [ ] Usability review done (is anything maybe unclear or think about anything that would cause people to reach out to support)
• [ ] Security review done
• [ ] Wording review done
• [ ] Code review done
• [ ] Tests were added if useful/possible
• [ ] Reviewed for breaking changes
• [ ] Developer changelog updated if needed
• [ ] Documentation added if needed
• [ ] Existing documentation updated if needed