[1pt] Switch badges for Missions - Conditional components

[NitBravoA92]

Missions that the user has joined already should show a badge "Active Member" instead of the default "NOT A MEMBER" and a button "Leave Mission" instead of the "Join Mission" button (as per design).

Use the React conditional rendering syntax:

{rocket.reserved && ( 
    // render Cancel Rocket button
)}

[Kidd254]

This is the link to the pull request #39