Revert WebApi-CSharp changes

For some reason I don't understand, this template doesn't see Random.Shared when compiled so this reverts the previous change for this template.

Author: martincostello

src/ProjectTemplates/Web.ProjectTemplates/content/WebApi-CSharp/Controllers/WeatherForecastController.cs

@@ -68,11 +68,12 @@ public async Task<IEnumerable<WeatherForecast>> Get()
                 throw new HttpRequestException($"Invalid status code in the HttpResponseMessage: {response.StatusCode}: {error}");
             }
 
+            var rng = new Random();
             return Enumerable.Range(1, 5).Select(index => new WeatherForecast
             {
                 Date = DateTime.Now.AddDays(index),
-                TemperatureC = Random.Shared.Next(-20, 55),
-                Summary = Summaries[Random.Shared.Next(Summaries.Length)]
+                TemperatureC = rng.Next(-20, 55),
+                Summary = Summaries[rng.Next(Summaries.Length)]
             })
             .ToArray();
         }
@@ -93,11 +94,12 @@ public async Task<IEnumerable<WeatherForecast>> Get()
             HttpContext.VerifyUserHasAnyAcceptedScope(scopeRequiredByApi);
             var user = await _graphServiceClient.Me.Request().GetAsync();
 
+            var rng = new Random();
             return Enumerable.Range(1, 5).Select(index => new WeatherForecast
             {
                 Date = DateTime.Now.AddDays(index),
-                TemperatureC = Random.Shared.Next(-20, 55),
-                Summary = Summaries[Random.Shared.Next(Summaries.Length)]
+                TemperatureC = rng.Next(-20, 55),
+                Summary = Summaries[rng.Next(Summaries.Length)]
             })
             .ToArray();
         }
@@ -114,11 +116,12 @@ public IEnumerable<WeatherForecast> Get()
             HttpContext.VerifyUserHasAnyAcceptedScope(scopeRequiredByApi);
 
 #endif
+            var rng = new Random();
             return Enumerable.Range(1, 5).Select(index => new WeatherForecast
             {
                 Date = DateTime.Now.AddDays(index),
-                TemperatureC = Random.Shared.Next(-20, 55),
-                Summary = Summaries[Random.Shared.Next(Summaries.Length)]
+                TemperatureC = rng.Next(-20, 55),
+                Summary = Summaries[rng.Next(Summaries.Length)]
             })
             .ToArray();
         }