Everywhere: Add sv suffix to strings relying on StringView(char const*)

Each of these strings would previously rely on StringView's char const*
constructor overload, which would call __builtin_strlen on the string.
Since we now have operator ""sv, we can replace these with much simpler
versions. This opens the door to being able to remove
StringView(char const*).

No functional changes.

Userland/Applications/PDFViewer/NumericInput.cpp

@@ -9,7 +9,7 @@
 
 NumericInput::NumericInput()
 {
-    set_text("0");
+    set_text("0"sv);
 
     on_change = [&] {
         auto number_opt = text().to_int();