Fix new Recommendations widget tip displaying at every launch

[Gio2018]

Summary

• This PR fixes a beta issue where the new Recommendations widget tip would show at every launch

References

• Branch name

Implementation Details

• Add Tips.Events to vend the tips, to have better control on when to display them

Test Steps

• build/run, make sure the new recommendations tip only shows once, regardless how you dismiss it

PR Checklist:

• Added Unit / UI tests
• Self Review (review, clean up, documentation, run tests)
• Basic Self QA

Screenshots

[pocket-ci]

	Messages
📖	No SwiftLint violations! 🎉
📖	Project coverage: 36.43%
📖	Checking XCode Environment Variables
📖	Edited 5 files
📖	Created 0 files

PocketKit: Coverage: 61.79

File	Coverage
ItemsListViewController.swift	77.36%	✅
HomeViewController.swift	61.22%	✅
TippableViewController.swift	47.0%	⚠️
ReadableViewController.swift	62.82%	✅
PocketTips.swift	100.0%	✅

PocketKitTests: Coverage: 28.37

File	Coverage
HomeViewController.swift	46.81%	⚠️
PocketTips.swift	100.0%	✅
ReadableViewController.swift	65.23%	✅
ItemsListViewController.swift	67.3%	✅
TippableViewController.swift	71.0%	✅

Generated by 🚫 Danger Swift against f9fd7fa