Empty decompoundedAttributes on payload throws error

- Algolia Client Version: 3.4.1
- Language Version:

### Description
I added a new Decompounded attribute ({"da":["name"]}) and removed it from Algolia dashboard. Then when I pulled online attributes using PHP connector, an empty decompoundedAttributes returned. After merging my local configs when I tried to save it, it throws the following error.
"nvalid array syntax in decompoundedAttributes attribute near line:1 column:354"

We tested with 4.x.x PHP Client and we couldn't reproduce it in there.

### Steps To Reproduce

1. Add a new decompounded attribute in Algolia dashboard
2. Now delete that attribute from Algolia dashboard
3. Pull online attributes
4. Now try to save those attributes again

### Actual result
Throws "nvalid array syntax in decompoundedAttributes attribute near line:1 column:354" error

### Expected result
Should save config without any error.