Simplify build profile loading logic (#762)

Removed unnecessary check for build profile define symbol.

dist/default-build-script/Assets/Editor/UnityBuilderAction/Builder.cs

@@ -66,10 +66,6 @@ namespace UnityBuilderAction
         var buildProfile = AssetDatabase.LoadAssetAtPath<BuildProfile>(buildProfilePath)
                            ?? throw new Exception("Build profile file not found at path: " + buildProfilePath);
 
-#if !BUILD_PROFILE_LOADED
-        throw new Exception("Build profile's define symbol not present before script execution; shouldn't happen");
-#endif // BUILD_PROFILE_LOADED
-
         // no need to set active profile, as already set by `-activeBuildProfile` CLI argument
         // BuildProfile.SetActiveBuildProfile(buildProfile);
         Debug.Log($"build profile: {buildProfile.name}");