Don't require immutable Yarn build

Since the project version is in the lock file, updating the version
during CI will cause the lock file to be updated

Build/BuildScripts/AEModule.build

@@ -45,7 +45,7 @@
   <Target Name="RunYarnWorkspace">
     <Message Importance="high" Text="Running Yarn for $(WorkingDirectory)" />
 
-    <Yarn Command="install --immutable" WorkingDirectory="$(WorkingDirectory)" IgnoreExitCode="false" Condition="$(WorkingDirectory.Length) > 0" />
+    <Yarn Command="install --no-immutable" WorkingDirectory="$(WorkingDirectory)" IgnoreExitCode="false" Condition="$(WorkingDirectory.Length) > 0" />
     <Yarn Command="build" WorkingDirectory="$(WorkingDirectory)" IgnoreExitCode="false" Condition="$(WorkingDirectory.Length) > 0" />
   </Target>
 </Project>