chore: improve compatibility for firefox (#38)

src/utils/index.mjs

@@ -5,6 +5,7 @@ export * from './fetch-sse'
 export * from './get-conversation-pairs'
 export * from './get-possible-element-by-query-selector'
 export * from './init-session'
+export * from './is-firefox.mjs'
 export * from './is-mobile'
 export * from './is-safari'
 export * from './limited-fetch'

src/utils/is-firefox.mjs

@@ -0,0 +1,3 @@
+export function isFirefox() {
+  return navigator.userAgent.includes('Firefox')
+}