Strip `external/local_tsl` prefix during zip of tsl protos
PR strips external/local_tsl prefix from tsl protos when packaging //tensorflow/tools/lib_package:libtensorflow_proto.zip.  See also #61883. Here's a head of the tree for the current zip archive to demonstrate the issue:

```.
 .
├── external
│   └── local_tsl
│       └── tsl
│           ├── profiler
│           │   └── protobuf
│           │       ├── profiler_options.proto
│           │       └── xplane.proto
│           └── protobuf
│               ├── bfc_memory_map.proto
│               ├── coordination_config.proto
│               ├── distributed_runtime_payloads.proto
│               ├── error_codes.proto
│               ├── histogram.proto
│               ├── rpc_options.proto
│               ├── status.proto
│               └── test_log.proto
└── tensorflow
    └── core
        ├── example
        │   ├── example.proto
        │   ├── example_parser_configuration.proto
        │   └── feature.proto
        ├── framework
        │   ├── allocation_description.proto
        │   ├── api_def.proto
        │   ├── attr_value.proto
        │   ├── cost_graph.proto
        │   ├── cpp_shape_inference.proto
        │   ├── dataset.proto
        │   ├── dataset_metadata.proto
        │   ├── dataset_options.proto
        │   ├── device_attributes.proto
   .
   .
   .
```


cc: @jakeharmon8 