Allow for spaces after chunk size when parsing HTTP with Transfer-Encoding: chunked

[ognjenMarinkovic27]

I've found that dart:http cannot parse HTTP chunk size when it contains spaces after the number, but before CRLF. In that case, it produces the error:

Failed to parse HTTP, 32 is expected to be a Hex digit

I've found this issue while working with ESPAsyncWebServer

Dart SDK Version: 3.0.5
OS: linux_x64

[a-siva]

A breaking change request to potentially fix this issue has been filed here #53005

[brianquinlan]

This will be fixed in Dart 3.2.0