fix: do not require browserStack config
fix: do not require browserStack config

Dignifiedquire/karma-browserstack-launcher,jackspirou/karma-browserstack-launcher,szarouski/karma-browserstack-launcher,karma-runner/karma-browserstack-launcher,luhmann/karma-browserstack-launcher,mzgol/karma-browserstack-launcher,shirish87/karma-browserstack-launcher