Everywhere: Remove DeprecatedFlyString + any remaining references to it

Author: https://github.com/kennethmyhra
Commit: 3131e6369f
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/4153

AK/StringView.cpp

@@ -7,7 +7,6 @@
 #include <AK/AnyOf.h>
 #include <AK/ByteBuffer.h>
 #include <AK/ByteString.h>
-#include <AK/DeprecatedFlyString.h>
 #include <AK/Find.h>
 #include <AK/FlyString.h>
 #include <AK/Function.h>
@@ -36,12 +35,6 @@ StringView::StringView(ByteString const& string)
 {
 }
 
-StringView::StringView(DeprecatedFlyString const& string)
-    : m_characters(string.characters())
-    , m_length(string.length())
-{
-}
-
 StringView::StringView(ByteBuffer const& buffer)
     : m_characters((char const*)buffer.data())
     , m_length(buffer.size())