[CMake] Don't check if Python headers are found in RootBuildOptions

This is a followup to 5e424e4, where the Python finding was moved into
`SearchInstalledSoftware.cmake`.

However, what I missed is that there was a check in `RootBuildOptions`
that disabled PyROOT by default if Python is not found, which is now not
the case at that point! Therefore, ROOT builds won't have PyROOT by
default anymore, which is a bad mistake.

Fortunately, the check is entirely redundant and this commit suggests to
remove it. There is already a check in `SearchInstalledSoftware` where
PyROOT (and `tmva-pymva`) are disabled when the Python development
headers where not found.

Author: guitargeek

cmake/modules/RootBuildOptions.cmake

@@ -314,12 +314,6 @@ elseif(APPLE)
   set(x11_defvalue OFF)
 endif()
 
-# Pyroot requires Python development package; force to OFF if it was not found
-if(NOT Python3_Development_FOUND)
-  set(pyroot_defvalue OFF)
-  set(tmva-pymva_defvalue OFF)
-endif()
-
 # Current limitations for modules:
 #---Modules are disabled on aarch64 platform (due ODR violations)
 if(CMAKE_SYSTEM_PROCESSOR MATCHES aarch64)