Changes empty static StringView, as it caused conflicts with older Empty bool checker.

tests/StringViewTests.cpp

@@ -77,7 +77,7 @@ TEST_CASE("Out of scope char* doesn't lose reference", "[Utilities]") {
 }
 
 TEST_CASE("Get Empty String", "[Utilities]") {
-    REQUIRE(ArbUt::StringView::Empty() == ""_cnc);
+    REQUIRE(ArbUt::StringView::EmptyString() == ""_cnc);
 }