Dev mode: fixed loading plugins located outside of the Flipper source root folder

Summary: Dev mode: fixed loading of plugins located outside of the Flipper source root folder, e.g. in ~/flipper-plugins as suggested in tutorial docs.

Reviewed By: passy

Differential Revision: D21306639

fbshipit-source-id: bb9044b25324065f0c12169b95fbe663da8d4305

.vscode/launch.json

@@ -20,8 +20,9 @@
       "type": "node",
       "request": "launch",
       "name": "Launch Current Jest Suite",
+      "cwd": "${workspaceFolder}/desktop",
       "program": "${workspaceFolder}/desktop/node_modules/.bin/jest",
-      "args": ["--runInBand", "${relativeFile}"]
+      "args": ["--runInBand", "${file}"]
     },
     {
       "type": "node",