Conflicts when installing via conda on Linux

- [x] I read [the conda-forge documentation](https://conda-forge.org/docs/user/introduction.html#how-can-i-install-packages-from-conda-forge) and could not find the solution for my problem there.

Issue:
I cannot install `kaleido-core` or `python-kaleido` (in example environment below):
```
UnsatisfiableError: The following specifications were found to be incompatible with each other:

Package python_abi conflicts for:
python=3.9 -> python_abi=3.9[build=*_cp39]
Package __glibc conflicts for:
kaleido-core -> __glibc[version='>=2.17,<3.0.a0']
Package tk conflicts for:
python=3.9 -> tk[version='>=8.6.10,<8.7.0a0']
Package readline conflicts for:
python=3.9 -> readline[version='>=8.0,<9.0a0|>=8.1,<9.0a0']
Package sqlite conflicts for:
kaleido-core -> sqlite[version='>=3.34.0,<4.0a0']
python=3.9 -> sqlite[version='>=3.33.0,<4.0a0|>=3.34.0,<4.0a0|>=3.35.4,<4.0a0|>=3.35.5,<4.0a0|>=3.36.0,<4.0a0']
Package tzdata conflicts for:
python=3.9 -> tzdata
Package fonts-conda-forge conflicts for:
kaleido-core -> fonts-conda-forge
Package xz conflicts for:
python=3.9 -> xz[version='>=5.2.5,<5.3.0a0|>=5.2.5,<6.0a0']
Package openssl conflicts for:
python=3.9 -> openssl[version='>=1.1.1h,<1.1.2a|>=1.1.1i,<1.1.2a|>=1.1.1j,<1.1.2a|>=1.1.1k,<1.1.2a']
Package zlib conflicts for:
python=3.9 -> zlib[version='>=1.2.11,<1.3.0a0']
Package ld_impl_linux-64 conflicts for:
python=3.9 -> ld_impl_linux-64[version='>=2.36.1']
Package pip conflicts for:
python=3.9 -> pip
Package nspr conflicts for:
kaleido-core -> nspr[version='>=4.29,<5.0a0']
Package fontconfig conflicts for:
kaleido-core -> fontconfig
Package libgcc-ng conflicts for:
python=3.9 -> libgcc-ng[version='>=7.3.0|>=7.5.0|>=9.3.0']
kaleido-core -> libgcc-ng[version='>=9.3.0']
Package ncurses conflicts for:
python=3.9 -> ncurses[version='>=6.2,<6.3.0a0|>=6.2,<7.0a0']
Package nss conflicts for:
kaleido-core -> nss[version='>=3.59,<4.0a0|>=3.62,<4.0a0']
Package libffi conflicts for:
python=3.9 -> libffi[version='>=3.2.1,<3.3.0a0|>=3.3,<3.4.0a0']
Package mathjax conflicts for:
kaleido-core -> mathjax=2.7
Package libstdcxx-ng conflicts for:
python=3.9 -> libstdcxx-ng[version='>=7.3.0|>=7.5.0|>=9.3.0']
Package expat conflicts for:
kaleido-core -> expat[version='>=2.2.10,<3.0.0a0|>=2.2.9,<3.0.0a0']
```

This also happens when making a new environment with e.g.
```
conda create -n plotly plotly scipy numpy pybind11 pandas hdbscan scikit-learn h5py libgomp libgfortran-ng openblas gsl 'cmake>=3.19' python-kaleido
```

I am not sure exactly what is conflicting here, but these are fairly standard packages to have installed. The only thing I wondered about was the `mathjax = 2.7` requirement.

This works on OS X however.

Any advice on what the conflict here might be, and whether it is resolvable, would be greatly appreciated.

Environment (conda list):

```
$ conda list
brotlipy 0.7.0 py39h3811e60_1001 conda-forge
bzip2 1.0.8 h7f98852_4 conda-forge
c-ares 1.17.2 h7f98852_0 conda-forge
ca-certificates 2021.5.30 ha878542_0 conda-forge
cached-property 1.5.2 hd8ed1ab_1 conda-forge
cached_property 1.5.2 pyha770c72_1 conda-forge
certifi 2021.5.30 py39hf3d152e_0 conda-forge
cffi 1.14.6 py39he32792d_0 conda-forge
chardet 4.0.0 py39hf3d152e_1 conda-forge
charset-normalizer 2.0.0 pyhd8ed1ab_0 conda-forge
cmake 3.21.2 h8897547_0 conda-forge
cryptography 3.4.7 py39hbca0aa6_0 conda-forge
expat 2.4.1 h9c3ff4c_0 conda-forge
gsl 2.7 he838d99_0 conda-forge
h5py 3.2.1 nompi_py39h98ba4bc_100 conda-forge
hdbscan 0.8.27 py39hce5d2b2_0 conda-forge
hdf5 1.10.6 nompi_h6a2412b_1114 conda-forge
icu 68.1 h58526e2_0 conda-forge
idna 3.1 pyhd3deb0d_0 conda-forge
joblib 1.0.1 pyhd8ed1ab_0 conda-forge
krb5 1.19.2 hcc1bbae_0 conda-forge
ld_impl_linux-64 2.36.1 hea4e1c9_2 conda-forge
libblas 3.9.0 11_linux64_openblas conda-forge
libcblas 3.9.0 11_linux64_openblas conda-forge
libcurl 7.78.0 h2574ce0_0 conda-forge
libedit 3.1.20191231 he28a2e2_2 conda-forge
libev 4.33 h516909a_1 conda-forge
libffi 3.3 h58526e2_2 conda-forge
libgcc-ng 11.1.0 hc902ee8_8 conda-forge
libgfortran-ng 11.1.0 h69a702a_8 conda-forge
libgfortran5 11.1.0 h6c583b3_8 conda-forge
libgomp 11.1.0 hc902ee8_8 conda-forge
liblapack 3.9.0 11_linux64_openblas conda-forge
libnghttp2 1.43.0 h812cca2_0 conda-forge
libopenblas 0.3.17 pthreads_h8fe5266_1 conda-forge
libssh2 1.10.0 ha56f1ee_0 conda-forge
libstdcxx-ng 11.1.0 h56837e0_8 conda-forge
libuv 1.42.0 h7f98852_0 conda-forge
lz4-c 1.9.3 h9c3ff4c_1 conda-forge
ncurses 6.2 h58526e2_4 conda-forge
nodejs 14.17.4 h92b4a50_0 conda-forge
numpy 1.21.2 py39hdbf815f_0 conda-forge
openblas 0.3.17 pthreads_h4748800_1 conda-forge
openssl 1.1.1k h7f98852_1 conda-forge
pandas 1.3.2 py39hde0f152_0 conda-forge
pip 21.2.4 pyhd8ed1ab_0 conda-forge
plotly 5.3.1 pyhd8ed1ab_0 conda-forge
plotly-orca 3.4.2 0 conda-forge
pp-sketchlib 1.7.4 py39hdefe18a_0 conda-forge
psutil 5.8.0 py39h3811e60_1 conda-forge
pybind11 2.7.1 py39h1a9c180_0 conda-forge
pybind11-global 2.7.1 py39h1a9c180_0 conda-forge
pycparser 2.20 pyh9f0ad1d_2 conda-forge
pyopenssl 20.0.1 pyhd8ed1ab_0 conda-forge
pysocks 1.7.1 py39hf3d152e_3 conda-forge
python 3.9.6 h49503c6_1_cpython conda-forge
python-dateutil 2.8.2 pyhd8ed1ab_0 conda-forge
python_abi 3.9 2_cp39 conda-forge
pytz 2021.1 pyhd8ed1ab_0 conda-forge
readline 8.1 h46c0cb4_0 conda-forge
requests 2.26.0 pyhd8ed1ab_0 conda-forge
rhash 1.4.1 h7f98852_0 conda-forge
scikit-learn 0.24.2 py39h4dfa638_1 conda-forge
scipy 1.7.1 py39hee8e79c_0 conda-forge
setuptools 57.4.0 py39hf3d152e_0 conda-forge
six 1.16.0 pyh6c4a22f_0 conda-forge
sqlite 3.36.0 h9cd32fc_0 conda-forge
tenacity 8.0.1 pyhd8ed1ab_0 conda-forge
threadpoolctl 2.2.0 pyh8a188c0_0 conda-forge
tk 8.6.11 h21135ba_0 conda-forge
tzdata 2021a he74cb21_1 conda-forge
urllib3 1.26.6 pyhd8ed1ab_0 conda-forge
wheel 0.37.0 pyhd8ed1ab_1 conda-forge
xz 5.2.5 h516909a_1 conda-forge
zlib 1.2.11 h516909a_1010 conda-forge
zstd 1.5.0 ha95c52a_0 conda-forge
```

Details about conda and system ( conda info ):

```
$ conda info
active environment : sce
active env location : /home/jlees/miniconda3/envs/sce
shell level : 5
user config file : /home/jlees/.condarc
populated config files : /home/jlees/.condarc
conda version : 4.7.12
conda-build version : not installed
python version : 3.7.4.final.0
virtual packages : __cuda=11.1
base environment : /home/jlees/miniconda3 (writable)
channel URLs : https://conda.anaconda.org/conda-forge/linux-64
https://conda.anaconda.org/conda-forge/noarch
https://conda.anaconda.org/bioconda/linux-64
https://conda.anaconda.org/bioconda/noarch
https://repo.anaconda.com/pkgs/main/linux-64
https://repo.anaconda.com/pkgs/main/noarch
https://repo.anaconda.com/pkgs/r/linux-64
https://repo.anaconda.com/pkgs/r/noarch
package cache : /home/jlees/miniconda3/pkgs
/home/jlees/.conda/pkgs
envs directories : /home/jlees/miniconda3/envs
/home/jlees/.conda/envs
platform : linux-64
user-agent : conda/4.7.12 requests/2.22.0 CPython/3.7.4 Linux/5.4.0-70-generic ubuntu/18.04.5 glibc/2.27
UID:GID : 1001:1001
netrc file : None
offline mode : False
```