Revert PR 25975 "Change devel build to use pybind11 for cmsRun"

[fabiocos]

This reverts commit fcf7e70.

PR description:

This PR replaces #26291 , updating in the same spirit 10_6_DEVEL_X to bring it in sync with 10_6_X, before merging #26278 .

PR validation:

This revert just make 10_6_X and 10_6_DEVEL_X branches coincide.

[cmsbuild]

A new Pull Request was created by @fabiocos (Fabio Cossutti) for CMSSW_10_6_DEVEL_X.

It involves the following packages:

FWCore/Framework

@cmsbuild, @smuzaffar, @Dr15Jones can you please review it and eventually sign? Thanks.
@makortel, @Martin-Grunewald, @wddgit this is something you requested to watch as well.
@davidlange6, @slava77, @fabiocos you are the release manager for this.

cms-bot commands are listed here

[fabiocos]

@davidlange6 I think that what you really mean with #26291 is now this. I cross checked that #26278 merges smoothly on top of this.

[fabiocos]

please test

[cmsbuild]

The tests are being triggered in jenkins.

[cmsbuild]

-1
Tested at: UNKNOWN
I was not able to find a release to test this PR. See the Jenkins logs for more details.

[davidlange6]

thanks - i don't think there is much point in figuring out how to test this..

[fabiocos]

+1

[fabiocos]

merge