Replace global Logging macros with inline functions

[tbhova]

Type

• Bug fix (non-breaking change which fixes an issue): Fixes #
• New feature (non-breaking change which adds functionality). Resolves #
• Breaking change (fix or feature that would cause existing functionality to not work as expected) Resolves #

Motivation and Context

cpp/open3d/utility/Logging.h previously defined LogError, LogWarning, LogInfo, and LogDebug as unprefixed preprocessor macros in the global preprocessor scope (#define LogError(...) Logger::LogError_(...)) to mimic a "macro in namespace" when callers write utility::LogError(...).

Because C++ preprocessor macros do not respect namespaces, including any Open3D header that transitively includes open3d/utility/Logging.h (such as open3d/geometry/TriangleMesh.h or open3d/geometry/PointCloud.h) pollutes the global macro namespace for the remainder of the translation unit. Any subsequently included third-party or application header that declares a method, function, or enum named LogError, LogWarning, LogInfo, or LogDebug (for example, custom logger interfaces or Abseil logging utilities) fails to compile because the preprocessor rewrites foo.LogError(...) into foo.Logger::LogError_(__FILE__, __LINE__, ...).

Checklist:

• I have run python util/check_style.py --apply to apply Open3D code style
  to my code.
• This PR changes Open3D behavior or adds new functionality.
  • Both C++ (Doxygen) and Python (Sphinx / Google style) documentation is
    updated accordingly.
  • I have added or updated C++ and / or Python unit tests OR included test
    results (e.g. screenshots or numbers) here.
• I will follow up and update the code if CI fails.
• For fork PRs, I have selected Allow edits from maintainers.

Description

Replaces the global #define LogError, #define LogWarning, #define LogInfo, and #define LogDebug macros in cpp/open3d/utility/Logging.h with inline variadic template functions inside namespace open3d::utility.

Why This Is Possible Now (Without Requiring C++20):
When Logging.h was originally written in 2019 (targeting C++14 and older compilers), preprocessor macros (__FILE__, __LINE__, OPEN3D_FUNCTION) were the only portable way to capture caller source locations because Clang (< 9.0, Sept 2019) and MSVC (< VS 2019 16.6 / _MSC_VER 1926, May 2020) did not yet implement the compiler intrinsics (__builtin_FILE(), __builtin_LINE(), __builtin_FUNCTION()) created to back C++20 std::source_location. Even though the <source_location> header itself requires C++20, all toolchains supported by Open3D today (GCC 7+, Clang 9+, AppleClang, MSVC VS 2019 16.6+, and NVCC) expose __builtin_FILE(), __builtin_LINE(), and __builtin_FUNCTION() in C++17 mode.

Why Functionality Is Equivalent:

1. Call-site syntax is unchanged: utility::LogError(...), open3d::utility::LogError(...), and unqualified LogError(...) (inside namespace open3d::utility or translation units with using namespace open3d::utility;) all resolve to the new inline function templates in namespace open3d::utility.
2. Caller source location (file, line, function) is still captured at the call site without C++20 <source_location> or macros: open3d::utility::detail::LogLocation wraps const char *format with a non-explicit constexpr constructor whose default arguments (__builtin_FILE(), __builtin_LINE(), __builtin_FUNCTION()) are evaluated at the caller's source location in C++17 across GCC, Clang, AppleClang, MSVC (VS 2019 16.6+), and NVCC.
3. Formatting and control-flow semantics are untouched: LogError, LogWarning, LogInfo, and LogDebug forward loc.file, loc.line, loc.function, loc.format, and std::forward<Args>(args)... directly to Logger::LogError_, Logger::LogWarning_, Logger::LogInfo_, and Logger::LogDebug_, preserving [[noreturn]] on LogError and existing fmt formatting behavior.

Testing:

• Extended cpp/tests/utility/Logging.cpp to verify that utility::LogError captures the caller's filename (Logging.cpp) and formatted message in the thrown std::runtime_error.
• Added Logging.NoGlobalMacroPollution in cpp/tests/utility/Logging.cpp to verify that a class defining LogError(), LogWarning(), LogInfo(), and LogDebug() member functions compiles and executes cleanly after including open3d/utility/Logging.h.

[update-docs]

Thanks for submitting this pull request! The maintainers of this repository would appreciate if you could update the CHANGELOG.md based on your changes.

[tbhova]

Thanks for submitting this pull request! The maintainers of this repository would appreciate if you could update the CHANGELOG.md based on your changes.

Done :)