LibGfx: Use float when calculating text width in ScaledFont

This fixes an issue where we'd truncate the fractional part of each
glyph width, often making the returned width slightly too short.

Userland/Libraries/LibGfx/Font/ScaledFont.cpp

@@ -19,8 +19,8 @@ ALWAYS_INLINE int ScaledFont::unicode_view_width(T const& view) const
 {
     if (view.is_empty())
         return 0;
-    int width = 0;
-    int longest_width = 0;
+    float width = 0;
+    float longest_width = 0;
     u32 last_code_point = 0;
     for (auto code_point : view) {
         if (code_point == '\n' || code_point == '\r') {