Switch AppSec rack blocking to throw

[y9v]

What does this PR do?
We want to have a unified way of blocking in AppSec and separate catch return arguments from Gateway#watch return arguments.

Motivation:
Reducing code complexity.

Change log entry
None.

Additional Notes:
None.

How to test the change?
CI and manual testing with app generator.

[datadog-datadog-prod-us1]

Datadog Report

Branch report: appsec-use-throw-for-rack-blocking
Commit report: 629e7b5
Test service: dd-trace-rb

✅ 0 Failed, 22196 Passed, 1476 Skipped, 5m 9.11s Total Time

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 97.71%. Comparing base (1d24f5d) to head (629e7b5).
Report is 3 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #4281      +/-   ##
==========================================
- Coverage   97.72%   97.71%   -0.01%     
==========================================
  Files        1354     1354              
  Lines       82416    82411       -5     
  Branches     4220     4213       -7     
==========================================
- Hits        80537    80527      -10     
- Misses       1879     1884       +5     

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[pr-commenter]

Benchmarks

Benchmark execution time: 2025-01-14 13:12:10

Comparing candidate commit 629e7b5 in PR branch appsec-use-throw-for-rack-blocking with baseline commit 1d24f5d in branch master.

Found 0 performance improvements and 0 performance regressions! Performance is the same for 31 metrics, 2 unstable metrics.

[Strech]

I think it would be cool to understand the end goal of adjustments because there is a common issue when step-by-step adjustments might lead to sub-par result without knowing what kind of design will be at the end.

[Strech]

We discuss this step and I don't have any concerns