Remove redundant call to `find_package`

We are in Overlap so MPI has already been found in top-level `CMakeLists.txt`.

Overlap/Tests/CMakeLists.txt

@@ -91,8 +91,6 @@ target_include_directories(test_write_overlap PRIVATE ${fortrangis_INCLUDE_DIR})
 
 # test_send_recv
 
-find_package(MPI REQUIRED)
-
 add_executable(test_send_recv
   ${CMAKE_CURRENT_LIST_DIR}/test_send_recv.f90 send_snapshot.f90
   recv_snapshot.f90 ${CMAKE_SOURCE_DIR}/Common/read_field_indices.f90