Fix IGWarnAssert macro to remove unneeded condition parameter

Summary:
I'm looking at updating IGKitKit's test suite for Xcode 15, but when I went to do a build, it failed at the `IGWarnAssert` macro. Turns out that because we set the condition in the macro to always return `(NO)`, there's no need to expose `frmt` to test for the condition.

This diff removes `frmt` from the define, allowing the tests to build again.

Reviewed By: fabiomassimo

Differential Revision:
D49628618

Privacy Context Container: L1203725

fbshipit-source-id: b0456a149bf5be96c8401a21866880ccd72ebbcb

Source/IGListDiffKit/IGListAssert.h

@@ -14,7 +14,7 @@
 #endif // IGWarn
 
 #ifndef IGWarnAssert
-#define IGWarnAssert(frmt, ... ) IGAssert( (NO) , ##__VA_ARGS__)
+#define IGWarnAssert( ... ) IGAssert( (NO) , ##__VA_ARGS__)
 #endif // IGWarnAssert
 
 #ifndef IGFailAssert