net-mgmt/netdata: Fix build with default python != 3.11

Wrong automatic generated usage of %%PYTHON_SUFFIX%% in plist.

PR: 288310
Approved by: Namkhai B. <nk@nkeor.me> (maintainer, implicit - fix build)
Fixes: f4b9bc1d0bfe (Update 2.6.1 => 2.6.3)