CI fixes post Python 3.12 support (#7020)

Remove python-3.12 branch ref from CI, don't build tf ops with Python 3.8

.github/workflows/macos.yml

@@ -214,6 +214,8 @@ jobs:
 
     env:
       BUILD_CUDA_MODULE: OFF
+      # TensorFlow v2.16 does not support Python 3.8
+      BUILD_TENSORFLOW_OPS: ${{ matrix.python_version == '3.8' && 'OFF' || 'ON' }}
       OPEN3D_ML_ROOT: ${{ github.workspace }}/Open3D-ML
     steps:
       - name: Checkout source code

.github/workflows/ubuntu-wheel.yml

@@ -153,7 +153,6 @@ jobs:
         uses: actions/checkout@v4
         with:
           repository: isl-org/Open3D-ML
-          ref: ss/python-3.12    # remove before merge
           path: ${{ env.OPEN3D_ML_ROOT }}
       - name: Download wheels
         uses: actions/download-artifact@v4

3rdparty/googletest/googletest.cmake

@@ -12,5 +12,5 @@ FetchContent_Declare(
     INSTALL_COMMAND ""
 )
 
-FetchContent_Populate(ext_googletest)
+FetchContent_MakeAvailable(ext_googletest)
 FetchContent_GetProperties(ext_googletest SOURCE_DIR GOOGLETEST_SOURCE_DIR)

cpp/pybind/t/geometry/lineset.cpp

@@ -257,20 +257,16 @@ transformation as :math:`P = R(P) + t`)");
 
 Args:
     angle (float): The rotation angle in degree.
-
     axis (open3d.core.Tensor): The rotation axis.
-
     resolution (int): The resolution defines the number of intermediate sweeps
         about the rotation axis.
-
     translation (float): The translation along the rotation axis.
 
 Returns:
     A triangle mesh with the result of the sweep operation.
 
 
 Example:
-
     This code generates a spring from a single line::
 
         import open3d as o3d
@@ -286,18 +282,16 @@ transformation as :math:`P = R(P) + t`)");
                  R"(Sweeps the line set along a direction vector.
 
 Args:
-
     vector (open3d.core.Tensor): The direction vector.
-
     scale (float): Scalar factor which essentially scales the direction vector.
 
 Returns:
     A triangle mesh with the result of the sweep operation.
 
 
 Example:
-
     This code generates an L-shaped mesh::
+
         import open3d as o3d
 
         lines = o3d.t.geometry.LineSet([[1.0,0.0,0.0],[0,0,0],[0,0,1]], [[0,1],[1,2]])
@@ -326,7 +320,7 @@ matrices. Camera reference frame is shown with XYZ axes in RGB.
 
 Example:
 
-    Draw a purple camera frame with XYZ axes in RGB.
+    Draw a purple camera frame with XYZ axes in RGB::
 
         import open3d.core as o3c
         from open3d.t.geometry import LineSet