Support Tips for new Twitter site

[emerick]

Fix brave/brave-browser#4548

Submitter Checklist:

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Verified that these changes build without errors on
  • Android
  • iOS
  • Linux
  • macOS
  • Windows
• Verified that these changes pass automated tests (unit, browser, security tests) on
  • iOS
  • Linux
  • macOS
  • Windows
• Verified that all lint errors/warnings are resolved (npm run lint)
• Ran git rebase master (if needed).
• Ran git rebase -i to squash commits (if needed).
• Tagged reviewers and labelled the pull request as needed.
• Request a security/privacy review as needed.
• Add appropriate QA labels (QA/Yes or QA/No) to include the closed issue in milestone
• Public documentation has been updated as necessary. For instance:
  • https://github.com/brave/brave-browser/wiki/Deviations-from-Chromium-(features-we-disable-or-remove)
  • https://github.com/brave/brave-browser/wiki/Proxy-redirected-URLs
  • https://github.com/brave/brave-browser/wiki/Fingerprinting-Protection-Mode
  • https://github.com/brave/brave-browser/wiki/Brave%E2%80%99s-Use-of-Referral-Codes
  • https://github.com/brave/brave-browser/wiki/Custom-Headers
  • https://github.com/brave/brave-browser/wiki/Web-compatibility-issues-with-tracking-protection
  • https://github.com/brave/brave-browser/wiki/QA-Guide

Test Plan:

All tests must be run on the old Twitter site and the new Twitter site. All functionality should work when logged in to Twitter and when logged out of Twitter.

Note: You can create a verified Twitter publisher by visiting this special link and following the Twitter flow:

https://publishers-staging.basicattentiontoken.org/publishers/home?twitter=true

Enabling/disabling the Brave Tip icon

• Launch Brave on a new profile and keep Brave Rewards disabled
• Visit twitter.com.
• Ensure that the BAT tip icon doesn't appear in the action section of any tweets.
• Enable Brave Rewards.
• Ensure that Brave tip icons dynamically appear in Twitter feed within a few seconds.
• Visit brave://rewards and uncheck "Twitter" in Tips Settings
• Ensure that the Brave tip icons dynamically disappear from the Twitter feed within a few seconds.
• Reenable Brave Rewards and the tip icons should appear again.
• Scroll far enough into the Twitter feed that new tweets dynamically load (infinite scroll) and ensure that the tip icons appear in the newly loaded tweets.
• Click on a tweet and ensure that the tip icons load in the new overlay window that appears.

Tipping a Twitter user

• Click on a Tip icon for a Twitter user and ensure that the tip overlay dialog shows the appropriate "compliment" message, the relevant tweet/date, and the full name and screen name of the Twitter user. The dialog should respect all of the privacy standards for verified/unverified users as with the standard Tip dialog, so please test with both verified and unverified Twitter users.
• The tip dialog should respect custom tip amounts, if any are set.
• Upon sending the tip, you should receive a thank you message and an offer to tweet your tip.
• Clicking the "Tweet Now" button should populate a new tab with a message and the relevant quoted tweet.
• The quoted tweet shouldn't contain any clickable links.
• Posting the tweet should work as expected, but please delete the tweet afterward for now.

Reviewer Checklist:

• New files have MPL-2.0 license header.
• Request a security/privacy review as needed.
• Adequate test coverage exists to prevent regressions
• Verify test plan is specified in PR before merging to source

After-merge Checklist:

• The associated issue milestone is set to the smallest version that the
  changes has landed on.
• All relevant documentation has been updated.

[petemill]

LGTM Great team work 🎆

[petemill]

Fixing conflict due to #2723 having just landed...

[petemill]

Needs rebase, doing now...

[petemill]

I pushed the rebase and added functionality to now show the Tip button if we cannot get the tweetId (some Promoted tweets in new twitter).

Since I pushed some code myself, may want to review that too @emerick