[Glitch] Use helpers to check environment in frontend (#2571)

Port 277e6968f5 to glitch-soc

Signed-off-by: Claire <claire.github-309c@sitedethib.com>
Co-authored-by: Renaud Chaput <renchap@gmail.com>

app/javascript/flavours/glitch/utils/environment.ts

@@ -0,0 +1,7 @@
+export function isDevelopment() {
+  return process.env.NODE_ENV === 'development';
+}
+
+export function isProduction() {
+  return process.env.NODE_ENV === 'production';
+}