[1pt] Implement mission leaving - Actions

[fobadara]

• Follow the same logic as with the "Join mission" - but you need to set the reserved key to false.
• Dispatch these actions upon click on the corresponding buttons.

[rachidelaid]

Hi @fobadara this task is done you can review it https://github.com/fobadara/rocket-space-missions/pull/35

[fobadara]

Hi @rachidelaid, kindly review this PR: https://github.com/fobadara/rocket-space-missions/pull/40