go_proto_compiler does not preserve runfiles on the plugin

Suppose you have a proto compiler like:
```
go_proto_compiler(
    name = "go_opaque",
    options = [
        "myargs=somehting",
    ],
    plugin = "//my/cool:plugin",
    visibility = ["//visibility:public"],
    deps = PROTO_RUNTIME_DEPS + WELL_KNOWN_TYPES_APIV2,
)
```
And the plugin uses runfiles, then those runfiles are not included in the sandbox.