[ISSUE #10924] Fix gRPC FIFO batch send ordering

[qianye1001]

What changed

• select a gRPC FIFO batch queue using its shared message group, so consecutive batches in the same FIFO stream use the same queue;
• validate batch constraints from the converted message list: supported and consistent type, FIFO message group, encoded size, and message count;
• reject a gRPC batch when any message explicitly uses bodyEncoding=GZIP; IDENTITY and ENCODING_UNSPECIFIED remain valid as uncompressed input;
• pass the complete message list through one Proxy send invocation, which the lower client encodes into one SEND_BATCH_MESSAGE request;
• expand a single Broker batch result into ordered per-message gRPC result entries;
• add activity-level and protocol-level regression coverage.

Why

For requests containing more than one message, SendMessageQueueSelector ignored messageGroup and used the normal queue-selection pipeline. Consecutive FIFO batches for the same message group could therefore select different queues and lose ordering.

The batch validation also did not explicitly enforce the constraints required by one Broker batch request at the gRPC boundary. A compressed body cannot be put into MessageBatch safely with the current Broker batch protocol, so compressed gRPC batches are rejected before the Broker invocation.

Fixes #10924.

Validation

JDK 8:

mvn -pl proxy -DskipITs -Dspotbugs.skip=true -Dcheckstyle.skip=true -Djacoco.skip=true \
  -Dtest=SendMessageActivityTest \
  -Dsurefire.failIfNoSpecifiedTests=false test

The gRPC activity test passed 16/16; all selected tests passed 17/17.

The protocol-level MQClientAPIExtTest#testSendMessageListAsync also passed and verifies one remoting invocation with request code SEND_BATCH_MESSAGE containing the complete batch.

[codecov-commenter]

Codecov Report

❌ Patch coverage is 84.81013% with 12 lines in your changes missing coverage. Please review.
✅ Project coverage is 48.37%. Comparing base (7eee0fc) to head (e963385).

Files with missing lines	Patch %	Lines
...mq/proxy/grpc/v2/producer/SendMessageActivity.java	84.00%	6 Missing and 6 partials ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##             develop   #10926      +/-   ##
=============================================
- Coverage      48.45%   48.37%   -0.09%     
+ Complexity     13588    13573      -15     
=============================================
  Files           1380     1380              
  Lines         101196   101242      +46     
  Branches       13130    13140      +10     
=============================================
- Hits           49038    48974      -64     
- Misses         46190    46272      +82     
- Partials        5968     5996      +28     

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