Move Throwable catch to ExtraProtobufGenerator.run

[mbland]

Description

This catches errors that happen at any point in ExtraProtobufGenerator.run, not just within handleCodeGeneratorRequest. This, in turn, prevents more cases of ProtoScalaPBRule aspect workers hanging. Part of #1482.

Motivation

As I started experimenting with updating gRPC and ScalaPB libs, I bumped the ScalaPB libs to 1.0.0-alpha.1 to try to resolve a problem. The ProtoScalaPBRule workers then started hanging again.

After pulling the catch ... Throwable block from #1630 up into ExtraProtobufGenerator.run, I got the following stack trace:

$ bazel build //test/proto/...

ERROR: .../external/com_google_protobuf/BUILD.bazel:334:14:
  ProtoScalaPBRule
  external/com_google_protobuf/wrappers_proto_jvm_extra_protobuf_generator_scalapb.srcjar
  failed: (Exit 1): scalapb_worker failed: error executing command
  (from target @com_google_protobuf//:wrappers_proto)

bazel-out/.../bin/src/scala/scripts/scalapb_worker
  ... (remaining 2 arguments skipped)

--jvm_extra_protobuf_generator_out: java.lang.IllegalAccessError:
  class scalapb.options.Scalapb$ScalaPbOptions tried to access method
  'com.google.protobuf.LazyStringArrayList
    com.google.protobuf.LazyStringArrayList.emptyList()'
  (scalapb.options.Scalapb$ScalaPbOptions and
   com.google.protobuf.LazyStringArrayList are in unnamed module
   of loader 'app')
      at scalapb.options.Scalapb$ScalaPbOptions.<init>(Scalapb.java:5021)
      at scalapb.options.Scalapb$ScalaPbOptions.<clinit>(Scalapb.java:11165)
      at scalapb.options.Scalapb.<clinit>(Scalapb.java:24184)
      at scalapb.options.compiler.Scalapb$.registerAllExtensions(Scalapb.scala:8)
      at scalarules.test.extra_protobuf_generator.ExtraProtobufGenerator$.run(ExtraProtobufGenerator.scala:48)
      at protocbridge.frontend.PluginFrontend$.$anonfun$runWithBytes$1(PluginFrontend.scala:51)
      at scala.util.Try$.apply(Try.scala:213)
      at protocbridge.frontend.PluginFrontend$.runWithBytes(PluginFrontend.scala:51)
      at protocbridge.frontend.PluginFrontend$.runWithInputStream(PluginFrontend.scala:121)
      at protocbridge.frontend.PosixPluginFrontend$.$anonfun$prepare$2(PosixPluginFrontend.scala:40)
      at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
      at scala.concurrent.impl.ExecutionContextImpl$DefaultThreadFactory$$anon$1$$anon$2.block(ExecutionContextImpl.scala:75)
      at java.base/java.util.concurrent.ForkJoinPool.managedBlock(ForkJoinPool.java:3118)
      at scala.concurrent.impl.ExecutionContextImpl$DefaultThreadFactory$$anon$1.blockOn(ExecutionContextImpl.scala:87)
      at scala.concurrent.package$.blocking(package.scala:146)
      at protocbridge.frontend.PosixPluginFrontend$.$anonfun$prepare$1(PosixPluginFrontend.scala:38)
      at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
      at scala.concurrent.Future$.$anonfun$apply$1(Future.scala:659)
      at scala.util.Success.$anonfun$map$1(Try.scala:255)
      at scala.util.Success.map(Try.scala:213)
      at scala.concurrent.Future.$anonfun$map$1(Future.scala:292)
      at scala.concurrent.impl.Promise.$anonfun$transform$1(Promise.scala:42)
      at scala.concurrent.impl.CallbackRunnable.run(Promise.scala:74)
      at java.base/java.util.concurrent.ForkJoinTask$RunnableExecuteAction.exec(ForkJoinTask.java:1426)
      at java.base/java.util.concurrent.ForkJoinTask.doExec(ForkJoinTask.java:290)
      at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(ForkJoinPool.java:1020)
      at java.base/java.util.concurrent.ForkJoinPool.scan(ForkJoinPool.java:1656)
      at java.base/java.util.concurrent.ForkJoinPool.runWorker(ForkJoinPool.java:1594)
      at java.base/java.util.concurrent.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:183)

java.lang.RuntimeException: Exit with code 1
     at scala.sys.package$.error(package.scala:30)
     at scripts.ScalaPBWorker$.work(ScalaPBWorker.scala:44)
     at io.bazel.rulesscala.worker.Worker.persistentWorkerMain(Worker.java:96)
     at io.bazel.rulesscala.worker.Worker.workerMain(Worker.java:49)
     at scripts.ScalaPBWorker$.main(ScalaPBWorker.scala:39)
     at scripts.ScalaPBWorker.main(ScalaPBWorker.scala)

ERROR: .../external/com_google_protobuf/BUILD.bazel:334:14
  scala @com_google_protobuf//:wrappers_proto failed:
  (Exit 1): scalapb_worker failed: error executing command
  (from target @com_google_protobuf//:wrappers_proto)

bazel-out/.../bin/src/scala/scripts/scalapb_worker
  ... (remaining 2 arguments skipped)

Bumping to protobuf v28.2 resolved the issue, at the expense of sacrificing Bazel 6 support, as v21.7 was the last to support Bazel 6. But this issue is orthogonal to the original gRPC test failure issue, which I'll address in a future change.