Failed Failed to run : undefined

### How did it happen?
1. I click any button of sketch git function, all response " Failed Failed to run : undefined"
2.
3.

### Error log

```
Failed to run: undefined

{
"pid": "26068",
"status": 72,
"stdout": ""
}

@/Users/kate.lin/Library/Application Support/com.bohemiancoding.sketch3/Plugins/Git.sketchplugin/Contents/Sketch/__commands_Add.js:1:10567
@/Users/kate.lin/Library/Application Support/com.bohemiancoding.sketch3/Plugins/Git.sketchplugin/Contents/Sketch/__commands_Add.js:1:15862
c@/Users/kate.lin/Library/Application Support/com.bohemiancoding.sketch3/Plugins/Git.sketchplugin/Contents/Sketch/__commands_Add.js:1:20189
@/Users/kate.lin/Library/Application Support/com.bohemiancoding.sketch3/Plugins/Git.sketchplugin/Contents/Sketch/__commands_Add.js:1:21330
@/Users/kate.lin/Library/Application Support/com.bohemiancoding.sketch3/Plugins/Git.sketchplugin/Contents/Sketch/__commands_Add.js:1:21269
@/Users/kate.lin/Library/Application Support/com.bohemiancoding.sketch3/Plugins/Git.sketchplugin/Contents/Sketch/__commands_Add.js:1:21302
__skpm_run@/Users/kate.lin/Library/Application Support/com.bohemiancoding.sketch3/Plugins/Git.sketchplugin/Contents/Sketch/__commands_Add.js:1:21607
__skpm_run@[native code]
```

Reproduce a Git action from the Sketch plugin and inspect the failure reported in the generated __commands_Add.js stack trace, including status 72 and the empty stdout. Trace the command execution far enough to identify why it returns “undefined,” then verify that the Sketch Git buttons complete without this error.

Written by the indexing model from the issue text.