fix(issue:4211) parse entities in comma list

[puckowski]

correctly parse all entities in a comma separated list such that all URLs are rewritten correctly

Resolves: #4211

Given:

root
├─index.html
├─asset
|   ├─rabbit
|   |    ├─hello.jpg
├─style
|   ├─rabbit
|   |    ├─index.less
|   |    ├─styles.less     

where index.less imports styles.less and styles.less has the following:

#root {
  --bg-compose: url('../../asset/rabbit/hello.jpg') no-repeat top center 100% 68px,
    url('../../asset/rabbit/hello.jpg') no-repeat 0px 67px 100% calc(100% - 67px - 67px),
    url('../../asset/rabbit/hello.jpg') no-repeat bottom center 100% 68px;
}

and index.html includes index.less and is served using ws, the output is:

#root {
  --bg-compose: url('http://192.168.0.17:8000/asset/rabbit/hello.jpg') no-repeat top center 100% 68px, url('http://192.168.0.17:8000/asset/rabbit/hello.jpg') no-repeat 0px 67px 100% calc(100% - 67px - 67px), url('http://192.168.0.17:8000/asset/rabbit/hello.jpg') no-repeat bottom center 100% 68px;
}

I ran all tests locally and they pass.

What:

Not all entities are parsed correctly in a comma separated list and may result in incorrect CSS output.

Why:

Users expect correct CSS output when using comma separated lists with valid CSS syntax.

Checklist:

• Documentation
• Added/updated unit tests
• Code complete