[Ruby] add special status msg interop test (#33990)

fixes #24176

```
./tools/run_tests/run_interop_tests.py -l ruby -s c++ --use_docker
No module named 'apiclient'
Seen --use_docker flag, will run interop tests under docker.

IMPORTANT: The changes you are testing need to be locally committed
because only the committed changes in the current branch will be
copied to the docker environment.
START: Building interop docker images.
PASSED: build_docker_ruby [time=479.4sec, retries=0:0]
PASSED: build_docker_c++ [time=686.0sec, retries=0:0]
SUCCESS: All docker images built successfully.
START: interop_server_c++
PASSED: cloud_to_cloud:ruby:c++_server:cancel_after_begin:tls [time=0.9sec, retries=0:0]
PASSED: cloud_to_cloud:ruby:c++_server:empty_unary:tls [time=1.0sec, retries=0:0]
PASSED: cloud_to_cloud:ruby:c++_server:empty_stream:tls [time=1.0sec, retries=0:0]
PASSED: cloud_to_cloud:ruby:c++_server:cancel_after_first_response:tls [time=1.0sec, retries=0:0]
PASSED: cloud_to_cloud:ruby:c++_server🏓tls [time=1.0sec, retries=0:0]
PASSED: cloud_to_cloud:ruby:c++_server:server_streaming:tls [time=1.0sec, retries=0:0]
PASSED: cloud_to_cloud:ruby:c++_server:client_streaming:tls [time=1.0sec, retries=0:0]
PASSED: cloud_to_cloud:ruby:c++_server:large_unary:tls [time=1.0sec, retries=0:0]
PASSED: cloud_to_cloud:ruby:c++_server:status_code_and_message:tls [time=0.8sec, retries=0:0]
PASSED: cloud_to_cloud:ruby:c++_server:unimplemented_method:tls [time=0.8sec, retries=0:0]
PASSED: cloud_to_cloud:ruby:c++_server:custom_metadata:tls [time=0.9sec, retries=0:0]
PASSED: cloud_to_cloud:ruby:c++_server:unimplemented_service:tls [time=0.8sec, retries=0:0]
PASSED: cloud_to_cloud:ruby:c++_server:client_compressed_streaming:tls [time=0.8sec, retries=0:0]
PASSED: cloud_to_cloud:ruby:c++_server:special_status_message:tls [time=0.8sec, retries=0:0]
PASSED: cloud_to_cloud:ruby:c++_server:client_compressed_unary:tls [time=0.8sec, retries=0:0]
PASSED: cloud_to_cloud:ruby:c++_server:timeout_on_sleeping_server:tls [time=1.8sec, retries=0:0]
SUCCESS: All tests passed
```

src/ruby/pb/test/client.rb

@@ -649,6 +649,22 @@ class NamedTests
 
   end
 
+  def special_status_message
+    code = GRPC::Core::StatusCodes::UNKNOWN
+    message = "\t\ntest with whitespace\r\nand Unicode BMP ☺ and non-BMP 😈\t\n"
+    req = SimpleRequest.new(
+      response_status: EchoStatus.new(code: code, message: message))
+    begin
+      resp = @stub.unary_call(req)
+      fail AssertionError, "GRPC::Unknown should have been raised."
+    rescue GRPC::Unknown => e
+      if e.details.force_encoding("UTF-8") != message
+        fail AssertionError,
+          "Expected message #{message}. Received: #{e.details}"
+      end
+    end
+  end
+
   def all
     all_methods = NamedTests.instance_methods(false).map(&:to_s)
     all_methods.each do |m|

tools/run_tests/run_interop_tests.py

@@ -555,7 +555,6 @@ class RubyLanguage:
         return (
             _SKIP_SERVER_COMPRESSION
             + _SKIP_DATA_FRAME_PADDING
-            + _SKIP_SPECIAL_STATUS_MESSAGE
             + _SKIP_GOOGLE_DEFAULT_CREDS
             + _SKIP_COMPUTE_ENGINE_CHANNEL_CREDS
             + _ORCA_TEST_CASES