[Android] Select the highest priority threat from SafetyNetClient.loo…

[AlexeyBarabash]

This PR changes the way how BraveSafeBrowsingApiHandler handles the case when SafetyNet reports more than one threat.
Before: the first one was taken.
Now: the most prioritized is taken, threats are arranged by priorities at SAFETY_NET_THREAT_PRIORITIES array.

SAFETY_NET_THREAT_PRIORITIES can be changed after the review, the test must be updated accordingly then.

The codes returned from https://testsafebrowsing.appspot.com/ are:

• (1) [A/W/M/L/C] Should show a phishing warning - 5 - SafetyNetJavaThreatType.SOCIAL_ENGINEERING
• (2) [A/W/M/L/C/D] Should show a malware warning - 4 - SafetyNetJavaThreatType.POTENTIALLY_HARMFUL_APPLICATION
• (4) [W/M/L/C] Should show a unwanted software warning - 3 - SafetyNetJavaThreatType.UNWANTED_SOFTWARE
• (6) [A/W/M/L/C] Should show a billing warning - 15 - SafetyNetJavaThreatType.BILLING

Resolves brave/brave-browser#41581

This is a follow-up for #25842.

Submitter Checklist:

• I confirm that no security/privacy review is needed and no other type of reviews are needed, or that I have requested them
• There is a ticket for my issue
• Used Github auto-closing keywords in the PR description above
• Wrote a good PR/commit description
• Squashed any review feedback or "fixup" commits before merge, so that history is a record of what happened in the repo, not your PR
• Added appropriate labels (QA/Yes or QA/No; release-notes/include or release-notes/exclude; OS/...) to the associated issue
• Checked the PR locally:
  • npm run test -- brave_browser_tests, npm run test -- brave_unit_tests wiki
  • npm run presubmit wiki, npm run gn_check, npm run tslint
• Ran git rebase master (if needed)

Reviewer Checklist:

• A security review is not needed, or a link to one is included in the PR description
• New files have MPL-2.0 license header
• Adequate test coverage exists to prevent regressions
• Major classes, functions and non-trivial code blocks are well-commented
• Changes in component dependencies are properly reflected in gn
• Code follows the style guide
• Test plan is specified in PR before merging

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, 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/Web-Compatibility-Exceptions-in-Brave
  • https://github.com/brave/brave-browser/wiki/QA-Guide
  • https://github.com/brave/brave-browser/wiki/P3A

Test Plan:

There is no a strict test plan, because I never saw the website which had more than one threat reported by SafetyNet.

The basic sanity check though is

1. Open https://testsafebrowsing.appspot.com/
2. For 1, 2, 4, 6 option the corresponding interstitial page with warning must be displayed.

[github-actions]

The security team is monitoring all repositories for certain keywords. This PR includes the word(s) "safebrowsing" and so security team members have been added as reviewers to take a look.

No need to request a full security review at this stage, the security team will take a look shortly and either clear the label or request more information/changes.

Notifications have already been sent, but if this is blocking your merge feel free to reach out directly to the security team on Slack so that we can expedite this check.

[SergeyZhukovsky]

++

[brave-builds]

Released in v1.73.49