Use ArgumentNullException.ThrowIfNull helper method

Did a simple search/replace on the whole repo (except the RSSDP project)
This reduces LOC and should improve performance (methods containing a throw statement don't get inlined)

```
if \((\w+) == null\)
\s+\{
\s+throw new ArgumentNullException\((.*)\);
\s+\}
```

```
ArgumentNullException.ThrowIfNull($1);
```

1 files changed, 1 insertions, 4 deletions

diff --git a/MediaBrowser.Controller/Entities/PeopleHelper.cs b/MediaBrowser.Controller/Entities/PeopleHelper.cs
index 687ce1ec8d..8571bfcea5 100644
--- a/MediaBrowser.Controller/Entities/PeopleHelper.cs
+++ b/MediaBrowser.Controller/Entities/PeopleHelper.cs
@@ -11,10 +11,7 @@ namespace MediaBrowser.Controller.Entities
     {
         public static void AddPerson(List<PersonInfo> people, PersonInfo person)
         {
-            if (person == null)
-            {
-                throw new ArgumentNullException(nameof(person));
-            }
+            ArgumentNullException.ThrowIfNull(person);
 
             if (string.IsNullOrEmpty(person.Name))
             {