home: Fix compose box not visible on focus in Firefox Android.

Fixes #34010

From version 132, Firefox now defaults to not resize the viewport
content but only the visual viewport. While this works well in
Chrome Android, it creates a buggy experience in Firefox Android
where the compose box is hidden under keyboard.

To fix it, we rollback to resizing content when keyboard is shown
on Firefox Android.

zerver/views/home.py

@@ -244,6 +244,7 @@ def home_real(request: HttpRequest) -> HttpResponse:
     csp_nonce = secrets.token_hex(24)
 
     user_permission_info = get_user_permission_info(user_profile)
+    is_firefox_android = "Firefox" in client_user_agent and "Android" in client_user_agent
 
     response = render(
         request,
@@ -254,6 +255,7 @@ def home_real(request: HttpRequest) -> HttpResponse:
             "csp_nonce": csp_nonce,
             "color_scheme": user_permission_info.color_scheme,
             "enable_gravatar": settings.ENABLE_GRAVATAR,
+            "is_firefox_android": is_firefox_android,
             "s3_avatar_public_url_prefix": settings.S3_AVATAR_PUBLIC_URL_PREFIX
             if settings.LOCAL_UPLOADS_DIR is None
             else "",