Add leaky_relu and leaky_relu_backward to the ltc_ts backend (#62053)
Test Plan:
```
test/cpp/build/test_ptltc --gtest_filter=AtenLtcTsTensorTest.TestLeakyRelu
test/cpp/build/test_ptltc --gtest_filter=AtenLtcTsTensorTest.TestLeakyReluBackward
```
Tasks: T94684755
