Did you resolve this?
I get the same error using macOS 13.6.7 (22G720) and conda 23.9.0.
EDIT:
Running the following command seems to have resolved the error for me (after activating the fenics conda environment):
export PKG_CONFIG_PATH=/Users/philipc/miniconda3/envs/fenics/lib/pkgconfig:$PKG_CONFIG_PATH
where /Users/philipc/miniconda3 is my local conda installation directory.