Upgrade patches from Chromium 81.0.4044.129 to Chromium 81.0.4044.138 (1.8.x).

[mkarolin]

Fixes brave/brave-browser#9632
Related PR: brave/brave-browser#9649

Uplift from #5463

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-Protections
  • 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:

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.

[bsclifton]

CI ran was successful, with one intermittent rewards related browser test failure on macOS:

12:15:23  [  FAILED  ] BraveRewardsBrowserTest.NotVerifiedWallet, where TypeParam =  and GetParam() =  (6143 ms)
12:15:23  [542/542] BraveRewardsBrowserTest.NotVerifiedWallet (6347 ms)
12:15:23  1 test failed:
12:15:23      BraveRewardsBrowserTest.NotVerifiedWallet (../../brave/components/brave_rewards/browser/rewards_service_browsertest.cc:2323)

This is a known issue; captured with brave/brave-browser#9339

PR is good to go- ready for consideration 😄

[kjozwiak]

Uplift into 1.8.x approved after deliberating with @brave/uplift-approvers.