[NT-226] Cancel Backing Integration

[ifbarrera]

📲 What

Integrates the cancel backing flow with the mutation. Note that this work does not include error handling.

🤔 Why

For the cancel backing flow.

🛠 How

• adds the CancelBackingMutation file and CancelBackingInput file, and adds a cancelBacking function to our ServiceType
• hooks up the cancel backing mutation to the cancelPledgeButton, plus adds handling for dismissing the keyboard on return
• sets up delegates to handle when the cancel mutation succeeds
• adds enabling/disabling behavior for the cancel pledge button

Note: the recording didn't properly capture the message banner animation. If you run it on a device the animation is working as expected.

👀 See

Trello, screenshots, external resources?

Cancel Pledge	Cancel Pledge Button Disabled

♿️ Accessibility

• Tap targets use minimum of 44x44 pts dimensions
• Works with VoiceOver
• Supports Dynamic Type

✅ Acceptance criteria

• On staging, back a project that has been created on staging. Then navigate to your backing, and on the Manage Pledge screen navigate to "Cancel your pledge". Enter a cancellation reason. Then tap "Yes, cancel it". You should see in the console that the input parameters for the mutation should include the field "note" with your cancellation reason. You should then be taken back to the project page and you should see the message banner with the message "You've cancelled your pledge.".

• Repeat the test above without entering a cancellation reason. Everything should work as expected.

[ksr-ci-bot]

	1 Warning
⚠️	Big PR

Generated by 🚫 Danger

[justinswart]

Nice, works well! Minor comments.

[justinswart]