Throw exception on unexpected failure of creation on enum value from configuration, rather than falling back to a default.

This shouldn't happen in practice due to the configuration validation (e.g. by ContentSettingsValidator), so any failure of parsing here should be considered an exception.

src/Umbraco.Core/Configuration/Models/ContentSettings.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using Umbraco.Core.Configuration.Models.Validation;
 using Umbraco.Core.Macros;
 
 namespace Umbraco.Core.Configuration.Models
@@ -31,7 +32,9 @@ namespace Umbraco.Core.Configuration.Models
             {
                 return Enum.TryParse<MacroErrorBehaviour>(MacroErrors, true, out var value)
                     ? value
-                    : MacroErrorBehaviour.Inline;
+                    : throw new InvalidOperationException(
+                        $"Parsing of {nameof(MacroErrors)} field value of {MacroErrors} was not recognised as a valid value of the enum {nameof(MacroErrorBehaviour)}. " +
+                        $"This state shouldn't have been reached as if the configuration contains an invalid valie it should be caught by {nameof(ContentSettingsValidator)}.");
             }
         }
 

src/Umbraco.Core/Configuration/Models/HostingSettings.cs

@@ -1,4 +1,5 @@
 using System;
+using Umbraco.Core.Configuration.Models.Validation;
 
 namespace Umbraco.Core.Configuration.Models
 {
@@ -18,7 +19,9 @@ namespace Umbraco.Core.Configuration.Models
             {
                 return Enum.TryParse<LocalTempStorage>(LocalTempStorageLocation, true, out var value)
                     ? value
-                    : LocalTempStorage.Default;
+                    : throw new InvalidOperationException(
+                        $"Parsing of {nameof(LocalTempStorageLocation)} field value of {LocalTempStorageLocation} was not recognised as a valid value of the enum {nameof(LocalTempStorage)}. " +
+                        $"This state shouldn't have been reached as if the configuration contains an invalid valie it should be caught by {nameof(HostingSettingsValidator)}.");
             }
         }
 

src/Umbraco.Core/Configuration/Models/ModelsBuilderSettings.cs

@@ -1,5 +1,6 @@
 using System;
 using Umbraco.Configuration;
+using Umbraco.Core.Configuration.Models.Validation;
 
 namespace Umbraco.Core.Configuration.Models
 {
@@ -31,7 +32,9 @@ namespace Umbraco.Core.Configuration.Models
             {
                 return Enum.TryParse<ModelsMode>(ModelsMode, true, out var value)
                     ? value
-                    : Configuration.ModelsMode.Nothing;
+                    : throw new InvalidOperationException(
+                        $"Parsing of {nameof(ModelsMode)} field value of {ModelsMode} was not recognised as a valid value of the enum {nameof(ModelsMode)}. " +
+                        $"This state shouldn't have been reached as if the configuration contains an invalid valie it should be caught by {nameof(ModelsBuilderSettingsValidator)}.");
             }
         }
 

src/Umbraco.Core/Configuration/Models/SmtpSettings.cs

@@ -26,7 +26,10 @@ namespace Umbraco.Core.Configuration.Models
             {
                 return Enum.TryParse<SmtpDeliveryMethod>(DeliveryMethod, true, out var value)
                     ? value
-                    : SmtpDeliveryMethod.Network;
+                    : throw new InvalidOperationException(
+                        $"Parsing of {nameof(DeliveryMethod)} field value of {DeliveryMethod} was not recognised as a valid value of the enum {nameof(SmtpDeliveryMethod)}. " +
+                        $"This state shouldn't have been reached as if the configuration contains an invalid valie it should be caught by {nameof(GlobalSettingsValidator)}.");
+
             }
         }