Update GitVersion to v6.6.0 and adjust related configurations

[PTKu]

This pull request updates the GitVersion tool and related configurations across the project to ensure compatibility with the latest version and to align with new configuration standards. The most important changes are grouped below:

GitVersion Tool and Package Updates:

• Updated the gitversion.tool version in .config/dotnet-tools.json from 5.12.0 to 6.6.0 to use the latest GitVersion CLI tool.
• Updated the GitVersion.MsBuild package reference in Directory.Packages.props from 5.10.3 to 6.6.0 for build consistency.
• Removed the PackageVersion update for GitVersion.MsBuild version 6.0.5 from src/utils/tests/AXOpen.Utils.Tests/axopen_utils_tests_L1.csproj to prevent conflicts and redundancy.

Configuration and Compatibility Adjustments:

• Refactored GitVersion.yml branch configuration to use label instead of tag, updated the prevent-increment-of-merged-branch-version property to the new prevent-increment format, and removed deprecated is-mainline fields for compatibility with GitVersion 6.x.
• Added GitVersionOutputFile property to cake/Build.csproj to specify output location for GitVersion metadata, supporting newer GitVersion workflows.