Migrate todos Vue app filtering to `GlFilteredSearch`

What does this MR do and why?

This replaces the dropdown filters with the GlFilteredSearch component in the todos Vue app.

This MR's main goal is to provide the same filters as previously available in the Vue app, but with the GlFilteredSearch component. For the sake of efficiency, and because this is still behind a feature flag, no test have been written yet. The plan going forward would be as follows:

1. Enable the Author filter.
2. Sync selected filters with the URL.
3. Write tests.

This should let us iterate as fast as possible so that we can enable the feature flag in a reasonable timeframe.

MR acceptance checklist

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Screenshots or screen recordings

Before	After

Placeholder

Full-text search is currently not supported, so we warn about it

How to set up and validate locally

1. Enable the todos_vue_application feature flag: echo "Feature.enable(:todos_vue_application)" | rails c.
2. Navigate to the Vue todos app: http://gdk.test:3000/dashboard/todos/vue
3. Filter out todos using the filtered search component.

Related to #483052 (closed)