Fix widevine loading failure due to different TeamID

[simonhong]

Set disable-library-validation entitlements for helper-app that
loads widevine library.

fix brave/brave-browser#5433

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:

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.

[simonhong]

helper-plugin-entitlements.plist has one more property(allow-unsigned-executable-memory).
Not sure helper needs that also.

[mkarolin]

According to the comment here https://chromium.googlesource.com/chromium/src/+/3fa9da4e877a, com.apple.security.cs.allow-unsigned-executable-memory required to run Flash content and NaCl modules. Not sure if widevine needs the same, but the approach with adding the other entitlement makes sense.

[simonhong]

@mkarolin Thanks for checking.
I think we don't need to add allow-unsigned-executable-memory for helper.
If this entitlement should be used for widevine, upstream also needs it.

[mkarolin]

LGTM

[bsclifton]

Ready for uplifts back to 0.68.x 😄
(after testing on Nightly, of course!)