refactor: 토큰 반환에 대한 에러 처리 개선

Author: opficdev

DevLog/Infra/Common/InfraLayerError.swift

@@ -38,6 +38,10 @@ enum EmailFetchError: Error, Equatable {
     }
 }
 
+enum TokenError: Error {
+    case invalidResponse
+}
+
 enum SocialLoginError: Error {
     case invalidOAuthState
     case failedToStartWebAuthenticationSession

DevLog/Infra/Service/SocialLogin/GithubAuthenticationService.swift

@@ -223,7 +223,7 @@ final class GithubAuthenticationService: NSObject, AuthenticationService {
                let customToken = data["customToken"] as? String {
                 return (accessToken, customToken)
             }
-            throw URLError(.badServerResponse)
+            throw TokenError.invalidResponse
         } catch {
             throw mapRequestTokensError(error)
         }