ENH: Improve AnisotropicDiffusionLBR tests

[hjmjohnson]

Closes #6283 (originally InsightSoftwareConsortium/ITKAnisotropicDiffusionLBR#26, @jhlegarreta).

Test-quality improvements for the ingested Modules/Filtering/AnisotropicDiffusionLBR: relocates the two test-only CLI headers out of include/, modernizes to ITK test macros, adds a LinearAnisotropicDiffusionLBRImageFilter GoogleTest, clarifies the usage message, removes noisy prints, and conforms to ITK style. All 16 image-regression baselines unchanged. Single squashed commit on current upstream/main.

Issue #6283 ask → change

Ask	Change
1 Headers out of include/	CoherenceEnhancingDiffusionCommandLine.h folded into test/CoherenceEnhancingDiffusionTest.cxx (anon namespace); dead LinearAnisotropicDiffusionCommandLine.h removed, replaced by a GoogleTest
2 ITK test macros	ITK_TRY_EXPECT_NO_EXCEPTION, ITK_GTEST_EXERCISE_BASIC_OBJECT_METHODS
3 Run-as-long-as-possible	New GoogleTest uses non-fatal EXPECT_* (aggregated status); the 16 image-regression tests intentionally keep per-invocation CTest --compare status
4 Arg-check message	Clear multi-line usage via itkGenericExceptionMacro (also fixes a latent silent-EXIT_SUCCESS on too-few-args)
5 Remove prints	Progress-to-cout observer + parameter/timing noise + dead commented debug block removed
6 ITK style	pre-commit run --all-files clean

Validation

Built with Module_AnisotropicDiffusionLBR only; all 16 functional --compare tests + Doxygen pass (baselines byte-identical), new LinearAnisotropicDiffusionLBRImageFilter.SmokeTest GoogleTest passes. KWStyle exercised by CI.

[jhlegarreta]

Thanks for doing this Hans.

[dzenanz]

This is the most likely cause of:

CMake Error at CMake/ITKModuleTest.cmake:281 (target_link_libraries):
  Target "AnisotropicDiffusionLBRGTestDriver" links to:

    GTest::gtest

  but the target was not found.  Possible reasons include:

    * There is a typo in the target name.
    * A find_package call is missing for an IMPORTED target.
    * An ALIAS target is missing.

Call Stack (most recent call first):
  Modules/Filtering/AnisotropicDiffusionLBR/test/CMakeLists.txt:12 (creategoogletestdriver)

reported here.