Remove major version numbers from install paths

[azeey]

Summary

Follow up to gazebo-tooling/release-tools#1244 and part of gazebo-tooling/release-tools#1446

This removes major version numbers from install paths since side-by-side installation is no longer supported. Removing the versions helps reduce the number of changes required when updating packaging files (e.g. homebrew formulae).

Here's the diff between the build/install_manifest.txt files of this and the main branch:

--- old_install_manifest.txt	2026-03-10 22:40:45
+++ new_install_manifest.txt	2026-03-10 22:41:03
@@ -139,3 +139,3 @@
-~/ws/rotary/install/lib/gz-rendering-10/engine-plugins/libgz-rendering-ogre.10.0.0~pre1.dylib
-~/ws/rotary/install/lib/gz-rendering-10/engine-plugins/libgz-rendering-ogre.10.dylib
-~/ws/rotary/install/lib/gz-rendering-10/engine-plugins/libgz-rendering-ogre.dylib
+~/ws/rotary/install/lib/gz-rendering/engine-plugins/libgz-rendering-ogre.10.0.0~pre1.dylib
+~/ws/rotary/install/lib/gz-rendering/engine-plugins/libgz-rendering-ogre.10.dylib
+~/ws/rotary/install/lib/gz-rendering/engine-plugins/libgz-rendering-ogre.dylib
@@ -274,3 +274,3 @@
-~/ws/rotary/install/lib/gz-rendering-10/engine-plugins/libgz-rendering-ogre2.10.0.0~pre1.dylib
-~/ws/rotary/install/lib/gz-rendering-10/engine-plugins/libgz-rendering-ogre2.10.dylib
-~/ws/rotary/install/lib/gz-rendering-10/engine-plugins/libgz-rendering-ogre2.dylib
+~/ws/rotary/install/lib/gz-rendering/engine-plugins/libgz-rendering-ogre2.10.0.0~pre1.dylib
+~/ws/rotary/install/lib/gz-rendering/engine-plugins/libgz-rendering-ogre2.10.dylib
+~/ws/rotary/install/lib/gz-rendering/engine-plugins/libgz-rendering-ogre2.dylib

Checklist

• Signed all commits for DCO
• Added a screen capture or video to the PR description that demonstrates the fix (as needed)
• Added tests
• Updated documentation (as needed)
• Updated migration guide (as needed)
• Consider updating Python bindings (if the library has them)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• Updated Bazel files (if adding new files). Created an issue otherwise.
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