Quick Start for Existing Users: Add notifications tour

[hassaanelgarem]

Part of #18388

Description

Added new Notifications tour

• Tour is identical when started from Home or Menu
• Tour has a task completion notice
• Spotlight is added to notifications tab bar button for the first step

NotificationsTour.mov

Testing Instructions

Initial screen: Site Menu

1. Make sure the initial screen is site menu
2. Enable quick start for existing site from debug menu
3. Start notifications task
4. Make sure notice gets dispalyed with correct copy
5. Make sure spotlight appears over the notifications tab button
6. Tap on the notifications button
7. Make sure the task complete notice is dispalyed and gets dismissed automatically after 5 seconds
8. Go back to site menu screen
9. Make sure notification task is marked as completed

Initial screen: Home

1. Make sure the initial screen is home
2. Enable quick start for existing site from debug menu
3. Start notifications task
4. Make sure notice gets dispalyed with correct copy
5. Make sure spotlight appears over the notifications tab button
6. Tap on the notifications button
7. Make sure the task complete notice is dispalyed and gets dismissed automatically after 5 seconds
8. Go back to home screen
9. Make sure notification task is marked as completed

Regression Notes

1. Potential unintended areas of impact
   N/A

2. What I did to test those areas of impact (or what existing automated tests I relied on)
   N/A

3. What automated tests I added (or what prevented me from doing so)
   N/A

PR submission checklist:

• I have completed the Regression Notes.
• I have considered adding unit tests for my changes.
• I have considered adding accessibility improvements for my changes.
• I have considered if this change warrants user-facing release notes and have added them to RELEASE-NOTES.txt if necessary.

[wpmobilebot]

You can test the changes in Jetpack from this Pull Request by:

• Clicking here or scanning the QR code below to access App Center
• Then installing the build number pr18443-9a97289 on your iPhone

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

[wpmobilebot]

You can test the changes in WordPress from this Pull Request by:

• Clicking here or scanning the QR code below to access App Center
• Then installing the build number pr18443-9a97289 on your iPhone

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

[momo-ozawa]

Looks like you need to update the unit tests, but otherwise LGTM -- works as described!