Complete verified uploads for Storage 10.0.11 release

[KSemenenko]

Summary

• Keep LocalFile.FileStream open after cloud provider downloads; callers own the returned stream. This repairs the release-blocking Dropbox failure and the same pattern in Google Drive, CloudKit, and OneDrive.
• Complete the verified immutable upload API introduced on main for 10.0.11: an identical retry also checks content encoding and exact metadata, so a blob at the same path with another owner or placement cannot be reused.
• Merging into main reruns the guarded 10.0.11 NuGet release workflow. The package is not published yet.

Verification

• Verified-upload Azure regressions: 2 passed, including metadata mismatch.
• Focused cloud provider HTTP tests: 5 passed.
• Default Storage suite: 480 passed, 3 expected skips.
• dotnet format ManagedCode.Storage.slnx --no-restore and Release build: passed.
• PR checks: build-and-test, browser-stress, CodeQL, and Analyze passed.

[codecov]

Codecov Report

❌ Patch coverage is 76.19048% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 49.62%. Comparing base (37364ce) to head (a0d9149).

Files with missing lines	Patch %	Lines
...de.Storage.Core/Primitives/VerifiedObjectUpload.cs	70.58%	2 Missing and 3 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #121      +/-   ##
==========================================
- Coverage   49.73%   49.62%   -0.11%     
==========================================
  Files         159      159              
  Lines        7977     7994      +17     
  Branches     1055     1061       +6     
==========================================
  Hits         3967     3967              
- Misses       3551     3565      +14     
- Partials      459      462       +3     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.