fix(deps): back to karma-browserstack-launcher 1.4 (#3361)

See karma-runner/karma-browserstack-launcher#152
Maybe the cause of our travis fails.

Author: johnjbarton

package.json

@@ -446,7 +446,7 @@
     "husky": "^0.14.3",
     "jasmine-core": "^3.4.0",
     "karma-browserify": "^6.0.0",
-    "karma-browserstack-launcher": "^1.5.1",
+    "karma-browserstack-launcher": "^1.4.0",
     "karma-chai": "^0.1.0",
     "karma-chrome-launcher": "^2.2.0",
     "karma-firefox-launcher": "*",