Revert "Globally include absl str_format header"

This reverts commit e1bf5b07.

indra/llcommon/llformat.h

@@ -28,8 +28,6 @@
 #ifndef LL_LLFORMAT_H
 #define LL_LLFORMAT_H
 
-#include "absl/strings/str_format.h"
-
 // Use as follows:
 // LL_INFOS() << llformat("Test:%d (%.2f %.2f)", idx, x, y) << LL_ENDL;
 //