PR #23718: Add missing hlo_argument_modes to the error message

Imported from GitHub PR https://github.com/openxla/xla/pull/23718

The `multihost_hlo_runner` supports five `--hlo_argument_mode` options, but existing error message lists only three modes.
This PR adds missing modes to the error message - specifically "use_zeros_as_input" and "uninitialized"

Additionally, the error message now uses raw string literals (R"()") to simplify the code and avoid unnecessary escape characters.
Copybara import of the project:

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f0abbde8f3cd514acfdfb68701483c73e77ef50e by Alexander Pivovarov <pivovaa@amazon.com>:

Add missing hlo_argument_modes to error message

Merging this change closes #23718

FUTURE_COPYBARA_INTEGRATE_REVIEW=https://github.com/openxla/xla/pull/23718 from apivovarov:fix_err_msg f0abbde8f3cd514acfdfb68701483c73e77ef50e
PiperOrigin-RevId: 736784501