v6.1.0-alpha.15

Features

• Core: Add viewMode to StoryContext (#12566)
• Addon-docs: Add converters between Flow types and storybook types (#12550)

Bug Fixes

• Addon-actions: Fix log flushing when story re-renders (#12500)
• Angular: Unsubscribe prop subscriptions (#12514)
• Addon-docs: Remove leading pipe if using raw value for Flow union (#12549)