PR #9354: Remove unused legalize_sparse_ops param from MlirToXlaComputation
PR #9354: Remove unused legalize_sparse_ops param from MlirToXlaComputation

Imported from GitHub PR https://github.com/openxla/xla/pull/9354

`xla::ParseMlirModuleStringAndConvertToXlaComputation` uses the same params as `xla::MlirToXlaComputation`.

New param `legalize_sparse_ops` was added to `xla::MlirToXlaComputation` on Sep 14, 2023. But this param is unused now.

1. It was decided to remove `legalize_sparse_ops` param from `xla::MlirToXlaComputation`.

2. `options` param has default value `{}` in `MlirToXlaComputation` decl and it is passed by value. In case func caller uses empty options we can simply omit passing `options` param to remove unnecessary obj copy.
Copybara import of the project:

--
9619fa34d03cf2229d3e4a14bc202f4adbe2d03b by Alexander Pivovarov <pivovaa@amazon.com>:

Remove unused legalize_sparse_ops param from MlirToXlaComputation

Merging this change closes #9354

FUTURE_COPYBARA_INTEGRATE_REVIEW=https://github.com/openxla/xla/pull/9354 from apivovarov:legalize_sparse_ops 9619fa34d03cf2229d3e4a14bc202f4adbe2d03b
