PWA Fix (#5432)

* PWA Fix

* SWが/api/へのリクエストに関与しないように

* fix semicolon

* Update base.pug

* Update base.pug

src/client/app/boot.js

@@ -98,15 +98,10 @@
 
 	// If mobile, insert the viewport meta tag
 	if (isMobile) {
-		const meta = document.createElement('meta');
-		meta.setAttribute('name', 'viewport');
-		meta.setAttribute('content',
-			'width=device-width,' +
-			'initial-scale=1,' +
-			'minimum-scale=1,' +
-			'maximum-scale=1,' +
-			'user-scalable=no');
-		head.appendChild(meta);
+		const viewport = document.getElementsByName("viewport").item(0);
+		viewport.setAttribute('content',
+			`${viewport.getAttribute('content')},minimum-scale=1,maximum-scale=1,user-scalable=no`);
+		head.appendChild(viewport);
 	}
 
 	// Switch desktop or mobile version