Introduce --emit_script_path_in_exec_request, which for `--script_p…

…ath` builds emits the `ExecRequest` over grpc with `ScriptPath` info.

`ScriptPath` contains the `--script_path` value as `script_path` and the run script contents as `script_contents`.

In addition, do not write the run script to the `--script_path` value and always set `should_exec` in the `ExecRequest` to false when `--emit_script_path_in_exec_request` is set.

Note: before this flag, `ExecRequest` was never emitted over grpc for `--script_path` builds. Now, the `ExecRequest` is emitted with `ScriptPath` info for `--script_path` `--emit_script_path_in_exec_request` builds.
PiperOrigin-RevId: 602514336

third_party/bazel/src/main/protobuf/command_server.proto

@@ -94,6 +94,14 @@ message ExecRequest {
   repeated EnvironmentVariable environment_variable = 3;
   repeated bytes environment_variable_to_clear = 4;
   bool should_exec = 5;
+  optional ScriptPath script_path = 6;
+}
+
+// Represents the --script_path value and the run script contents for
+// relevant run builds.
+message ScriptPath {
+  bytes script_path = 1;
+  bytes script_contents = 2;
 }
 
 // Contains metadata and result data for a command execution.