[BUG] Incorrect comparison prevents PMC_HEU from being assigned in registration test

[ChengGMR]

Describe the bug
Hi TEASER++ team, I found a small issue that consistently generates a warning whenever I compile the TEASER++ library.

In test/teaser/registration-test.cc, the QUATRO rotation test uses the equality comparison operator (==) instead of the assignment operator (=) when setting params.inlier_selection_mode:

params.inlier_selection_mode ==
    teaser::RobustRegistrationSolver::INLIER_SELECTION_MODE::PMC_HEU;

This produces the following compiler warning:

warning: equality comparison result unused [-Wunused-comparison]

Because the comparison result is discarded, PMC_HEU is not assigned to params.inlier_selection_mode, and the test may run using the default inlier-selection mode instead of the intended configuration.

The line should be changed to:

params.inlier_selection_mode =
    teaser::RobustRegistrationSolver::INLIER_SELECTION_MODE::PMC_HEU;

Have you run the unit tests?

• Yes
• No --- then this issue will be closed.

Installed Dependencies

• OS: [Please add OS and version]
• Compiler: [Please add compiler and version]
• TEASER++ version or commit: [Please add version or commit]
• Other dependencies: [Please add dependency versions]

To Reproduce

1. Build TEASER++ with compiler warnings enabled.
2. Compile test/teaser/registration-test.cc.
3. Observe the warning around line 191:

TEASER-plusplus/test/teaser/registration-test.cc:191:34:
warning: equality comparison result unused [-Wunused-comparison]