refactor: Improve ordering of headers with clang-format (#5343)

Removes all manual header groupings from source and header files by leveraging clang-format options.

src/test/protocol/STIssue_test.cpp

@@ -18,6 +18,7 @@
 //==============================================================================
 
 #include <test/jtx.h>
+
 #include <xrpl/beast/unit_test.h>
 #include <xrpl/protocol/STIssue.h>
 
@@ -161,4 +162,4 @@ public:
 BEAST_DEFINE_TESTSUITE(STIssue, ripple_data, ripple);
 
 }  // namespace test
-}  // namespace ripple
+}  // namespace ripple