Fix Json deserializion of string containing hyphens to List<string> property

[ryangribble]

Issue

As discussed in #1026, there is an issue with the Json parser in a specific edge case.

When deserialising a string property into a class where that property is declared as a List<string> (as is the case with the responses from the Enterprise SearchIndexing API), hyphens in the string are stripped during deserialization.

Json
{ "message":"User \"ryan-gribble\" was added to the indexing queue" }

Class
public class MessageList { public IReadOnlyList<string> Message { get; private set; } }

Result
"User \"ryangribble\" was added to the indexing queue"

Expected Result
"User \"ryan-gribble\" was added to the indexing queue"

Resolution

This line (introduced in #727) was identified as responsible for the removal of the hyphens in the input string. Code inspection indicates the line appears to be unnecessary for the actual Enum and Nullable Enum cases mentioned when the change was made, as they already had code to remove hyphens in their if blocks.

Unit tests were added to assert expected behaviour when deserializing a string attribute containing hyphens (and underscores for good measure) into string and <IReadOnlyList<string> properties.

After confirming the latter test failed, the offending line was removed and the tests then passed.

All other unit and integration tests were then also passed, indicating that no other known/tested functionality are impacted by the removal.

[ryangribble]

@shiftkey Linux build failure looks unrelated to me. Looks like a timeout in the octokit.tests-portable

[shiftkey]

The only reservation I had was that this value was being used elsewhere and some enum values depended on this, but then I saw those places were calling RemoveHyphenAndUnderscore and saw it had us covered:

static string RemoveHyphenAndUnderscore(string stringValue)
{
    // remove '-' from values coming in to be able to enum utf-8
    stringValue = stringValue.Replace("-", "");
    // remove '-' from values coming in to be able to enum EventInfoState names with underscores in them. Like "head_ref_deleted" 
    stringValue = stringValue.Replace("_", "");
    return stringValue;
}

[shiftkey]

@ryangribble thanks for getting to the bottom of this, and for adding in those tests!