Add tabs to the pipeline schedules table refactor

What does this MR do and why?

This adds the tabs to the pipeline schedule table for the ongoing refactor to Vue for the pipeline schedules feature

#371989 (closed)

Screenshots or screen recordings

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Enable the pipeline_schedules_vue feature flag:

> bundle exec rails c
> Feature.enable(:pipeline_schedules_vue)

2. Go to a project and from there go to Pipelines -> Schedules
3. Verify that the tabs are there as well as the New Schedule button

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.