Swift Testing for Unit Tests PART 1 (#5119)

* migrated a lot of unit tests to Swift Testing and added a new implementation for deferred fulfillment

more tests migration

Cleaned the code manually to establish some good patterns

more code improvements

some more code improvements

removed empty tests

update project

* more pr suggestions and cleanups

* removed the TestSetup pattern

* fixing claude not reusing tests

* pr suggestion + added indent rule to swiftformat so that we can prevent AIs to change that

UnitTests/SupportingFiles/UnitTests.xctestplan

@@ -21,6 +21,7 @@
   },
   "testTargets" : [
     {
+      "parallelizable" : false,
       "target" : {
         "containerPath" : "container:ElementX.xcodeproj",
         "identifier" : "32C23C8D224D46EFE62AFAD0",