Improve mascot size

src/components/Intro/MascotIntroEnd.js

         <Mascot
           style={{
             ...styles.center,
-            width: '100%',
+            width: '80%',
           }}
           emotion={MASCOT_STYLE.COOL}
           animated

src/components/Intro/MascotIntroWelcome.js

         <Mascot
           style={{
             ...styles.center,
-            width: '100%',
+            width: '80%',
           }}
           emotion={MASCOT_STYLE.NORMAL}
           animated