fix(test): Disable reachability callbacks in SentryBreadcrumbTrackingIntegrationTests and check integration registers generated breadcrumbs

[itaybre]

📜 Description

Changes performed:

• Disabled reachability callback so it doesn't generate breadcrumbs automatically during our tests
• Fixed the test so it call the integration add(breadcrumb) instead of adding it to the SDK Manually

#skip-changelog

💡 Motivation and Context

Reachability breadcrumbs made the test flaky

💚 How did you test it?

📝 Checklist

You have to check all boxes before merging:

• I added tests to verify the changes.
• No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
• I updated the docs if needed.
• I updated the wizard if needed.
• Review from the native team if needed.
• No breaking change or entry added to the changelog.
• No breaking change for hybrid SDKs or communicated to hybrid SDKs.

Closes #7426

[github-actions]

Semver Impact of This PR

🟢 Patch (bug fixes)

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.297%. Comparing base (c431600) to head (1cab77f).
⚠️ Report is 19 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@              Coverage Diff              @@
##              main     #7425       +/-   ##
=============================================
- Coverage   85.327%   85.297%   -0.031%     
=============================================
  Files          481       485        +4     
  Lines        28612     28859      +247     
  Branches     12440     12580      +140     
=============================================
+ Hits         24414     24616      +202     
- Misses        4153      4200       +47     
+ Partials        45        43        -2     

see 17 files with indirect coverage changes

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