[GIE] Refine FFI interface build_physical_plan (#2911)

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## What do these changes do?
Return physical plan bytes from ffi interface `build_physical_plan`
directly, instead of wrapping the physical plan in the JobRequest, which
was previously bound to the pegasus engine API.

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## Related issue number

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Fixes

---------

Co-authored-by: BingqingLyu <bingqing.lbq@alibaba-inc.com>

interactive_engine/compiler/src/main/java/com/alibaba/graphscope/common/client/RpcExecutionClient.java

@@ -26,6 +26,7 @@
 import com.alibaba.pegasus.RpcClient;
 import com.alibaba.pegasus.intf.ResultProcessor;
 import com.alibaba.pegasus.service.protocol.PegasusClient;
+import com.google.protobuf.ByteString;
 
 import io.grpc.Status;
 
@@ -49,7 +50,9 @@ public RpcExecutionClient(Configs graphConfig, ChannelFetcher<RpcChannel> channe
     public void submit(ExecutionRequest request, ExecutionResponseListener listener)
             throws Exception {
         PegasusClient.JobRequest jobRequest =
-                PegasusClient.JobRequest.parseFrom((byte[]) request.getRequestPhysical().build());
+                PegasusClient.JobRequest.newBuilder()
+                        .setPlan(ByteString.copyFrom((byte[]) request.getRequestPhysical().build()))
+                        .build();
         PegasusClient.JobConfig jobConfig =
                 PegasusClient.JobConfig.newBuilder()
                         .setJobId(request.getRequestId())

interactive_engine/compiler/src/main/java/com/alibaba/graphscope/gremlin/plugin/processor/IrStandardOpProcessor.java

@@ -48,6 +48,7 @@
 import com.alibaba.pegasus.intf.ResultProcessor;
 import com.alibaba.pegasus.service.protocol.PegasusClient;
 import com.google.common.collect.ImmutableList;
+import com.google.protobuf.ByteString;
 import com.google.protobuf.InvalidProtocolBufferException;
 
 import org.antlr.v4.runtime.tree.ParseTree;
@@ -377,7 +378,10 @@ protected void processTraversal(
         byte[] physicalPlanBytes = irPlan.toPhysicalBytes(configs);
         irPlan.close();
 
-        PegasusClient.JobRequest request = PegasusClient.JobRequest.parseFrom(physicalPlanBytes);
+        PegasusClient.JobRequest request =
+                PegasusClient.JobRequest.newBuilder()
+                        .setPlan(ByteString.copyFrom(physicalPlanBytes))
+                        .build();
         PegasusClient.JobConfig jobConfig =
                 PegasusClient.JobConfig.newBuilder()
                         .setJobId(jobId)
@@ -423,7 +427,9 @@ protected void processRelNode(
                         jobName,
                         physicalBuilder.explain());
                 PegasusClient.JobRequest request =
-                        PegasusClient.JobRequest.parseFrom(physicalPlanBytes);
+                        PegasusClient.JobRequest.newBuilder()
+                                .setPlan(ByteString.copyFrom(physicalPlanBytes))
+                                .build();
                 PegasusClient.JobConfig jobConfig =
                         PegasusClient.JobConfig.newBuilder()
                                 .setJobId(jobId)