Add github action workflow that checks the build of sage in a conda environment, completely bypassing the installation of any sage package. This is based on the steps outlined at https://wiki.sagemath.org/Conda.

This also tests that the generated src/environment*.yml files work correctly. (See documentation added in #28745)

Run: https://github.com/sagemath/sagetrac-mirror/actions/workflows/ci-conda.yml

Fixes:

• Conda: Add primecountpy #33330: primecountpy is not installed in the conda env because its not listed in environment.yml
• environment-optional: lcalc 1 is installed and then not recognized / leads to error

building 'sage.libs.lcalc.lcalc_Lfunction' extension
    cc1plus: warning: command line option '-Wstrict-prototypes' is valid for C/ObjC but not for C++
    In file included from sage/libs/lcalc/lcalc_Lfunction.cpp:740:
    sage/libs/lcalc/lcalc_sage.h:1:10: fatal error: lcalc/L.h: No such file or directory
        1 | #include "lcalc/L.h"
          |          ^~~~~~~~~~~
    compilation terminated.

• environment-optional: probably related, pari 2.11.4 is installed by conda instead of the newest 2.13.2. This version is then rejected by configure as being too old.
• Disable conda distro information for gdb because it is broken on macOS.
• Add conda distro information for lrcalc_python
• Filter out conda-specific ld warnings in doctests
• In the feature test for sage_spkg, check whether any Sage packages are actually installed
• Include an upper version bound for ptyprocess in sagemath-standard's install-requires

Follow-ups: See Meta-ticket #33331

Depends on #33358
Depends on #33330
Depends on #33361
Depends on #33141

CC: @isuruf @tobiasdiez @dimpase @saraedum

Component: build

Keywords: sd111

Author: Tobias Diez, Matthias Koeppe

Branch/Commit: 93fce5a

Reviewer: Matthias Koeppe, Dima Pasechnik, Tobias Diez

Issue created by migration from https://trac.sagemath.org/ticket/30845