Everywhere: Rename {Deprecated => Byte}String

This commit un-deprecates DeprecatedString, and repurposes it as a byte
string.
As the null state has already been removed, there are no other
particularly hairy blockers in repurposing this type as a byte string
(what it _really_ is).

This commit is auto-generated:
  $ xs=$(ack -l \bDeprecatedString\b\|deprecated_string AK Userland \
    Meta Ports Ladybird Tests Kernel)
  $ perl -pie 's/\bDeprecatedString\b/ByteString/g;
    s/deprecated_string/byte_string/g' $xs
  $ clang-format --style=file -i \
    $(git diff --name-only | grep \.cpp\|\.h)
  $ gn format $(git ls-files '*.gn' '*.gni')

Userland/Libraries/LibJS/Runtime/Array.cpp

@@ -261,10 +261,10 @@ ThrowCompletionOr<double> compare_array_elements(VM& vm, Value x, Value y, Funct
     }
 
     // 5. Let xString be ? ToString(x).
-    auto x_string = PrimitiveString::create(vm, TRY(x.to_deprecated_string(vm)));
+    auto x_string = PrimitiveString::create(vm, TRY(x.to_byte_string(vm)));
 
     // 6. Let yString be ? ToString(y).
-    auto y_string = PrimitiveString::create(vm, TRY(y.to_deprecated_string(vm)));
+    auto y_string = PrimitiveString::create(vm, TRY(y.to_byte_string(vm)));
 
     // 7. Let xSmaller be ! IsLessThan(xString, yString, true).
     auto x_smaller = MUST(is_less_than(vm, x_string, y_string, true));