Introduce a button named New Objective in issues list

What does this MR do and why?

1. Swap Objective and Cancel button
2. objective within the Create objective button shouldn't be capitalized.
3. Adding some space (16px) under the input when the buttons wrap to increase usability on small screens.
4. Use the split dropdown for creating a new objective (more design details here)
5. Hide objective creation form until the Add objective button has triggered and then hide the form again once the objective has been created
6. Focus on Input on click of New Objective

Screenshots or screen recordings

https://www.loom.com/share/673e723212984eb78b2b5e98f7fbc0be

How to set up and validate locally

1. Need to have Ultimate License
2. Enable okrs_mvc feature flag

   Feature.enable(:okrs_mvc, Project.find(:id))

3. Visit the project for which feature flag is enabled, pages such as http://127.0.0.1:3000/flightjs/Flight/-/issues
4. Click New Issue dropdown and you should see New objective as option and on click will objective create form below filters
5. Enter title and create and objective
6. Once created, new Objective will be listed on the top of the list.
7. On click of cancel, hide the form.

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.