Shortcuts update part 1: remove existing shortcuts

[charliescheer]

Fix

We are reimplementing the current shortcuts using Siri kit intents. This will open up a lot more interesting possibilities for shortcuts, it will also add the intents into shortcuts automatically, (where our current system is using donation to add the intents which means they may not appear in shortcuts) This is going to happen in several steps and the first one is to drop the existing NSUserActivity donation so it no longer is contributed to shortcuts.

Test

Run this PR and then go to the shortcuts app -> Create a new shortcut - > Add action -> Find Simplenote and confirm you don't have new note or open note (you will still see publish to Wordpress, that comes from elsewhere and I don't think needs to be replaced)

Review

(Required) Add instructions for reviewers. For example:

Only one developer is required to review these changes, but anyone can perform the review.

Release

These changes do not require release notes.

[wpmobilebot]

You can test the changes in simplenote-ios from this Pull Request by:

• Clicking here or scanning the QR code below to access App Center
• Then installing the build number pr1578-c60cea2-018f4090-6c92-4d2a-9ee2-cd8e8d260013 on your iPhone

If you need access to App Center, please ask a maintainer to add you.

[jleandroperez]