fix jest transpiling all node modules, make tests fast again

the previous regexp is bugged, it requires '//' in the filename !!
As a result, all the files in node_modules don't pass the regex
so nothing is ignored => everything is transformed

jest caches this in /tmp/jest_* so rerunning tests is fast, but
the first time jest takes minutes to transform everything

Author: jonenst

package.json

@@ -54,7 +54,7 @@
             "\\.svg": "<rootDir>/src/__mocks__/svgrMock.js"
         },
         "transformIgnorePatterns": [
-            "node_modules/(?!@gridsuite/commons-ui)/"
+            "node_modules/(?!@gridsuite/commons-ui)"
         ]
     },
     "eslintConfig": {