ci(csharp): split e2e integration tests per target framework

[lukaszzborek]

After vsr changes, there are starting more containers then before.
Propably runner don't have to much power to start that amount of containers for both .net framework.
This pr split both frameworks to seperate runners

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.77%. Comparing base (3e7bf7a) to head (d883635).

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #3874      +/-   ##
============================================
- Coverage     82.84%   82.77%   -0.08%     
  Complexity     1299     1299              
============================================
  Files          1199     1199              
  Lines        161885   161887       +2     
  Branches     131360   131466     +106     
============================================
- Hits         134120   134000     -120     
- Misses        24225    24232       +7     
- Partials       3540     3655     +115     

Components	Coverage Δ
Rust Core	83.34% <ø> (-0.02%)	⬇️
Java SDK	66.06% <ø> (ø)
C# SDK	74.61% <ø> (-1.36%)	⬇️
Python SDK	89.98% <ø> (ø)
PHP SDK	84.26% <ø> (ø)
Node SDK	96.21% <ø> (ø)
Go SDK	68.53% <ø> (ø)
see 74 files with indirect coverage changes

🚀 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.